
Speed vs Velocity: Differences, Formula, Examples | JKSSB Finance Accounts Assistant
Understanding the concepts of speed and velocity is essential for mastering the topic of motion in General Science. Although these terms are often used interchangeably in everyday life, they have different meanings in physics. Questions related to speed, velocity, distance, and displacement are frequently asked in competitive examinations, including the JKSSB Finance Accounts Assistant (FAA) exam.
Speed tells us how fast an object is moving, while velocity describes both the speed and the direction of motion. A clear understanding of these concepts helps aspirants solve numerical problems, identify conceptual differences, and answer objective questions accurately.
In this article, we will discuss the meaning of speed and velocity, their formulas, SI units, key differences, numerical examples, important one-liners, and exam-oriented MCQs. The content is designed to provide a quick yet comprehensive revision for JKSSB Finance Accounts Assistant aspirants.
What is Speed?
Speed is one of the most fundamental concepts in physics used to describe the motion of an object. It tells us how fast an object is moving from one place to another. Whenever we talk about a car moving at 80 km/h, a train running at 100 km/h, or a person walking at 5 km/h, we are referring to their speed.
In simple words, speed is the distance travelled by an object in a given period of time. The greater the distance covered in a certain time, the higher the speed of the object. Similarly, if an object covers a shorter distance in the same amount of time, its speed is lower.
For example, if a car travels 60 kilometres in one hour, its speed is 60 km/h. If another car travels 80 kilometres in the same hour, its speed is 80 km/h. Thus, the second car is moving faster.
Formula of Speed
Speed is calculated by dividing the total distance travelled by the total time taken.
Speed = Distance Travelled ÷ Time Taken
This formula can also be rearranged as:
- Distance = Speed × Time
- Time = Distance ÷ Speed
These formulas are frequently used in competitive examinations to solve numerical problems related to motion.
SI Unit of Speed
The standard international (SI) unit of speed is metre per second (m/s). This means the distance covered in metres during one second.
For example:
- A speed of 10 m/s means an object travels 10 metres every second.
- A speed of 25 m/s means an object travels 25 metres every second.
In everyday life, speed is commonly measured in kilometres per hour (km/h).
Some common examples are:
- Walking speed of a person: approximately 5 km/h
- Speed of a bicycle: approximately 15 km/h
- Speed of a car on a highway: 60–100 km/h
- Speed of an airplane: around 800 km/h
Why is Speed Called a Scalar Quantity?
Speed is known as a scalar quantity because it has only magnitude and no direction. It only tells us how fast an object is moving and does not indicate the direction of motion.
For instance, if a vehicle is moving at 50 km/h, speed tells us only the value of motion (50 km/h). It does not tell whether the vehicle is moving north, south, east, or west.
Because direction is not considered, speed is always expressed as a positive value or zero.
Types of Speed
1. Uniform Speed
An object is said to move with uniform speed when it covers equal distances in equal intervals of time.
For example, if a train covers 60 km every hour continuously, it is moving with uniform speed. In real life, perfectly uniform speed is rare because most vehicles experience changes in speed due to traffic, turns, or road conditions.
2. Non-Uniform Speed
An object has non-uniform speed when it covers unequal distances in equal intervals of time or when its speed changes during motion.
For example, a bus travelling through a crowded city road frequently accelerates and slows down due to traffic signals and congestion. Therefore, it moves with non-uniform speed.
Most moving objects around us exhibit non-uniform speed.
3. Average Speed
In practical situations, the speed of an object often changes during its journey. In such cases, average speed is used to describe the overall motion.
Average speed is defined as the total distance travelled divided by the total time taken.
Average Speed = Total Distance Travelled ÷ Total Time Taken
For example, suppose a person travels 120 km in 3 hours. The average speed will be:
Average Speed = 120 ÷ 3 = 40 km/h
This means that although the person’s speed may have varied during the journey, the overall speed for the entire trip is 40 km/h.
Importance of Speed in Daily Life
The concept of speed is used in many practical situations, such as:
- Measuring the speed of vehicles on roads.
- Determining travel time between two places.
- Calculating the performance of athletes in sports.
- Designing transportation systems.
- Monitoring aircraft and railway movement.
Speed helps us compare the motion of different objects and understand which object is moving faster or slower.
Key Points
- Speed is the distance travelled per unit time.
- Speed is a scalar quantity because it has magnitude only.
- Speed does not depend on direction.
- The SI unit of speed is metre per second (m/s).
- The commonly used unit of speed is kilometre per hour (km/h).
- Speed depends on distance travelled, not displacement.
- Speed can be positive or zero but never negative.
- Average speed is equal to total distance divided by total time.
- Uniform speed means equal distances in equal intervals of time.
- Non-uniform speed means unequal distances in equal intervals of time.
Quick Revision Fact: Speed tells us only “how fast” an object moves, whereas velocity tells us both “how fast” and “in which direction” the object moves.
What is Velocity?
Velocity is the rate at which an object changes its position in a particular direction. In simple terms, velocity is speed with direction. While speed tells us only how fast an object is moving, velocity tells us both how fast the object is moving and the direction in which it is moving.
For example, if a car is moving at 60 km/h, this describes its speed. However, if we say the car is moving at 60 km/h towards Srinagar, we are describing its velocity because the direction of motion is also specified.
Velocity is an important concept in physics because the direction of motion often matters. Two objects may have the same speed but different velocities if they are moving in different directions.
Formula of Velocity
Velocity is calculated by dividing the displacement of an object by the time taken.
Velocity = Displacement ÷ Time
The formula can also be rearranged as:
- Displacement = Velocity × Time
- Time = Displacement ÷ Velocity
Unlike speed, which depends on distance travelled, velocity depends on displacement.
SI Unit of Velocity
The SI unit of velocity is metre per second (m/s).
Some other commonly used units are:
- Kilometre per hour (km/h)
- Centimetre per second (cm/s)
For example:
- A velocity of 20 m/s east means the object moves 20 metres every second towards the east.
- A velocity of 15 m/s north means the object moves 15 metres every second towards the north.
Why is Velocity a Vector Quantity?
Velocity is called a vector quantity because it has both magnitude and direction.
For instance:
- 50 km/h is a speed.
- 50 km/h towards north is a velocity.
Without direction, velocity cannot be completely described.
Velocity and Displacement
The concept of displacement is crucial for understanding velocity.
Displacement is the shortest straight-line distance between the initial and final positions of an object along with its direction.
Consider a person who walks 100 metres east and then 100 metres west, returning to the starting point.
- Total distance travelled = 200 metres
- Displacement = 0 metres
Since displacement is zero, the average velocity of the person is also zero, even though the person covered a distance of 200 metres.
This example clearly shows the difference between speed and velocity.
Types of Velocity
1. Uniform Velocity
An object is said to have uniform velocity when it covers equal displacements in equal intervals of time while moving in the same direction.
For example, a train moving straight at a constant speed of 60 km/h towards a particular direction has uniform velocity.
2. Variable Velocity
An object has variable velocity when either its speed changes, its direction changes, or both change with time.
For example:
- A car moving through city traffic.
- A ball thrown into the air.
- A vehicle moving along a curved road.
In all these cases, the velocity changes continuously.
Positive, Negative and Zero Velocity
Positive Velocity
When an object moves in the chosen positive direction, its velocity is considered positive.
Example: A vehicle moving east when east is taken as the positive direction.
Negative Velocity
When an object moves opposite to the chosen positive direction, its velocity is considered negative.
Example: A vehicle moving west when east is taken as the positive direction.
Negative velocity does not mean the object is moving slowly; it only indicates the direction of motion.
Zero Velocity
An object has zero velocity when there is no change in its position with time.
Example: A parked car or a stationary person.
Real-Life Examples of Velocity
- A train moving at 80 km/h towards Jammu.
- A cyclist travelling at 15 km/h northward.
- An airplane flying at 900 km/h towards Delhi.
- A river flowing at 5 m/s downstream.
In each example, both magnitude and direction are specified, making them examples of velocity.
Key Points
- Velocity is the displacement covered per unit time.
- Velocity is a vector quantity because it has both magnitude and direction.
- Velocity depends on displacement, not distance.
- The SI unit of velocity is metre per second (m/s).
- Velocity can be positive, negative, or zero.
- If displacement is zero, average velocity is zero.
- Speed without direction is not velocity.
- A change in either speed or direction causes a change in velocity.
Quick Revision Fact: Every velocity has speed, but every speed is not velocity because speed does not include direction.
Speed Formula and Velocity Formula
Speed and velocity are two fundamental concepts used to describe the motion of an object. Although both indicate how fast an object moves, they are calculated using different quantities. Speed is related to the total distance travelled, whereas velocity is related to the displacement of the object. A proper understanding of these formulas is important for solving numerical problems and conceptual questions frequently asked in JKSSB and other competitive examinations.
Formula of Speed
Speed is defined as the distance travelled by an object in a unit interval of time. It tells us how quickly an object covers a certain distance.
Speed = Distance Travelled ÷ Time Taken
This formula shows that speed depends on two factors:
- The distance covered by the object.
- The time taken to cover that distance.
If the distance travelled increases while the time remains the same, the speed increases. Similarly, if the same distance is covered in less time, the speed also increases.
Example 1
A student travels 100 kilometres in 2 hours.
Speed = Distance ÷ Time
Speed = 100 km ÷ 2 h
Speed = 50 km/h
Therefore, the speed of the student is 50 km/h.
Example 2
A cyclist covers 120 metres in 20 seconds.
Speed = 120 ÷ 20
Speed = 6 m/s
Therefore, the speed of the cyclist is 6 m/s.
Understanding the Speed Formula
The speed formula can be used in three different ways:
Finding Speed
When distance and time are given, speed can be calculated.
Example:
A train covers 240 km in 4 hours.
Speed = 240 ÷ 4 = 60 km/h
Finding Distance
When speed and time are known, distance can be calculated.
Distance = Speed × Time
Example:
A car moves at 50 km/h for 4 hours.
Distance = 50 × 4
Distance = 200 km
Finding Time
When distance and speed are known, time can be calculated.
Time = Distance ÷ Speed
Example:
A bus covers 180 km at a speed of 60 km/h.
Time = 180 ÷ 60
Time = 3 hours
These three formulas are frequently used in competitive examinations.
Formula of Velocity
Velocity is defined as the displacement of an object per unit time in a specific direction. It tells us not only how fast an object is moving but also the direction of motion.
Velocity = Displacement ÷ Time Taken
The major difference between speed and velocity lies in the use of displacement instead of distance.
Example
A person walks 60 metres east in 10 seconds.
Velocity = Displacement ÷ Time
Velocity = 60 ÷ 10
Velocity = 6 m/s east
Thus, the velocity of the person is 6 m/s east.
Notice that the direction “east” is included in the answer because velocity is a vector quantity.
Why Does Velocity Use Displacement?
Many students confuse distance with displacement.
- Distance is the actual path travelled by an object.
- Displacement is the shortest straight-line distance between the initial and final positions, along with direction.
Consider a person walking 50 metres east and then 50 metres west.
- Total distance travelled = 100 metres
- Displacement = 0 metres
If the total time taken is 20 seconds:
Speed = 100 ÷ 20 = 5 m/s
Velocity = 0 ÷ 20 = 0 m/s
This example clearly shows that speed and velocity can have different values.
Relationship Between Velocity, Displacement and Time
Just as the speed formula can be rearranged, the velocity formula can also be rearranged.
Finding Displacement
Displacement = Velocity × Time
Example:
A runner moves with a velocity of 8 m/s north for 10 seconds.
Displacement = 8 × 10
Displacement = 80 metres north
Finding Time
Time = Displacement ÷ Velocity
Example:
An object moves 150 metres east with a velocity of 30 m/s.
Time = 150 ÷ 30
Time = 5 seconds
Speed Formula vs Velocity Formula
Although the formulas look similar, the quantity used in the numerator makes all the difference.
| Speed | Velocity |
| Uses distance travelled | Uses displacement |
| Scalar quantity | Vector quantity |
| Direction not required | Direction required |
| Cannot be negative | Can be positive, negative, or zero |
| Depends on path length | Depends on initial and final positions |
Quick Formula Revision
| Quantity | Formula |
| Speed | Distance ÷ Time |
| Distance | Speed × Time |
| Time | Distance ÷ Speed |
| Velocity | Displacement ÷ Time |
| Displacement | Velocity × Time |
| Time | Displacement ÷ Velocity |
Key Points for JKSSB Exams
- Speed is the distance travelled per unit time.
- Velocity is the displacement covered per unit time.
- Distance is used to calculate speed.
- Displacement is used to calculate velocity.
- Speed does not require direction.
- Velocity always includes direction.
- Speed is a scalar quantity.
- Velocity is a vector quantity.
- Speed is always positive or zero.
- Velocity can be positive, negative, or zero.
Difference Between Speed and Velocity
Speed and velocity are closely related concepts in physics, and many students often use them interchangeably. However, they are not the same. The primary difference is that speed describes only how fast an object moves, whereas velocity describes both how fast and in which direction the object moves.
Meaning of Speed and Velocity
Speed is the distance travelled by an object per unit time. It tells only the rate of motion and does not provide any information about direction.
Velocity is the displacement of an object per unit time in a specific direction. It describes both the rate of motion and the direction of movement.
For example:
- A car moving at 60 km/h describes speed.
- A car moving at 60 km/h towards Jammu describes velocity.
Distance vs Displacement
The most important difference between speed and velocity lies in the quantities used for their calculation.
- Speed is based on distance travelled.
- Velocity is based on displacement.
Distance refers to the actual path covered by an object, while displacement refers to the shortest straight-line distance between the initial and final positions along with direction.
Because distance and displacement are often different, speed and velocity may also differ.
Scalar Quantity vs Vector Quantity
Speed is a scalar quantity, which means it has only magnitude.
For example:
- 40 km/h
- 10 m/s
Velocity is a vector quantity, which means it has both magnitude and direction.
For example:
- 40 km/h north
- 10 m/s east
Without direction, velocity cannot be completely specified.
Direction of Motion
Direction plays no role in speed.
Suppose a person is running at 8 m/s. This value tells us only how fast the person is moving.
However, if we say the person is running at 8 m/s towards the north, we are describing velocity because direction has been included.
Sign of Speed and Velocity
Speed is always positive or zero because distance can never be negative.
Examples:
- 50 km/h
- 20 m/s
- 0 m/s
Velocity, on the other hand, can be positive, negative, or zero depending on the chosen direction of motion.
For example:
- +20 m/s may indicate motion towards the east.
- -20 m/s may indicate motion towards the west.
- 0 m/s indicates no displacement.
Example Showing the Difference
Consider a student who walks 100 metres east and then returns 100 metres west to the starting point.
Distance Travelled
Distance = 100 + 100 = 200 metres
Displacement
Displacement = 0 metres (because the final position is the same as the initial position)
If the total time taken is 40 seconds:
Speed = Distance ÷ Time
Speed = 200 ÷ 40 = 5 m/s
Velocity = Displacement ÷ Time
Velocity = 0 ÷ 40 = 0 m/s
This example clearly shows that an object can have a non-zero speed but zero velocity.
Comparison Between Speed and Velocity
| Basis of Comparison | Speed | Velocity |
| Definition | Distance travelled per unit time | Displacement per unit time |
| Type of Quantity | Scalar quantity | Vector quantity |
| Direction Required | No | Yes |
| Depends On | Distance | Displacement |
| Can be Negative | No | Yes |
| Can be Zero | Yes | Yes |
| Formula | Distance ÷ Time | Displacement ÷ Time |
| Information Provided | How fast an object moves | How fast and in which direction it moves |
When Are Speed and Velocity Equal?
The numerical values of speed and velocity become equal when:
- The object moves in a straight line.
- The direction of motion does not change.
- Distance travelled is equal to displacement.
For example, if a car travels 100 metres east in a straight line, both speed and velocity will have the same numerical value.
Key Differences for Quick Revision
- Speed is based on distance, whereas velocity is based on displacement.
- Speed is a scalar quantity, whereas velocity is a vector quantity.
- Speed does not require direction, whereas velocity requires direction.
- Speed is always positive or zero, whereas velocity can be positive, negative, or zero.
- Speed tells only the rate of motion, whereas velocity tells the rate and direction of motion.
- Speed can never be negative, but velocity can be negative.
Quick Revision Fact: Every velocity has a speed associated with it, but every speed is not a velocity because speed does not include direction.
Distance and Displacement: The Key Difference Behind Speed and Velocity
To fully understand the difference between speed and velocity, it is essential to understand the concepts of distance and displacement. These two terms appear similar, but they have different meanings in physics. In fact, the main difference between speed and velocity arises because speed uses distance while velocity uses displacement.
Many students lose marks in competitive examinations because they confuse these two concepts. Therefore, a clear understanding of distance and displacement is very important for JKSSB Finance Accounts Assistant aspirants.
What is Distance?
Distance is the total length of the actual path travelled by an object during its motion.
It does not take direction into account and only measures how much ground has been covered.
For example, if a person walks 100 metres east and then 50 metres west, the total distance travelled will be:
Distance = 100 + 50 = 150 metres
Distance is always positive because the length of a path cannot be negative.
Characteristics of Distance
- Distance is the actual path travelled by an object.
- It is a scalar quantity.
- It has only magnitude and no direction.
- It is always positive or zero.
- Distance can never be less than displacement.
What is Displacement?
Displacement is the shortest straight-line distance between the initial position and the final position of an object, along with its direction.
Unlike distance, displacement considers both magnitude and direction.
Using the previous example:
A person walks 100 metres east and then 50 metres west.
- Initial position = Starting point
- Final position = 50 metres east of the starting point
Therefore,
Displacement = 50 metres east
Notice that the displacement is not 150 metres because displacement depends only on the starting and ending positions.
Characteristics of Displacement
- Displacement is the shortest path between two points.
- It is a vector quantity.
- It has both magnitude and direction.
- It can be positive, negative, or zero.
- Its magnitude is always less than or equal to distance.
Distance vs Displacement: Example 1
Suppose a student walks from point A to point B along a curved road of length 500 metres.
- Distance travelled = 500 metres
- Straight-line distance between A and B = 300 metres
Therefore:
- Distance = 500 metres
- Displacement = 300 metres
This example shows that distance is generally greater than displacement.
Distance vs Displacement: Example 2
Consider a runner completing one full lap of a circular track.
Assume the circumference of the track is 400 metres.
After completing one lap:
- Distance travelled = 400 metres
- Final position = Starting position
Therefore:
- Distance = 400 metres
- Displacement = 0 metres
This is one of the most important examples asked in competitive examinations.
Why Distance and Displacement Matter?
The difference between speed and velocity is directly related to distance and displacement.
Speed Depends on Distance
Speed measures how much distance an object covers in a given time.
Speed = Distance ÷ Time
Velocity Depends on Displacement
Velocity measures how much displacement occurs in a given time.
Velocity = Displacement ÷ Time
Because distance and displacement may have different values, speed and velocity may also have different values.
Major Differences Between Distance and Displacement
| Distance | Displacement |
| Total path travelled by an object | Shortest distance between initial and final positions |
| Scalar quantity | Vector quantity |
| No direction involved | Direction is involved |
| Always positive | Can be positive, negative, or zero |
| Depends on actual path followed | Depends only on initial and final positions |
| Greater than or equal to displacement | Less than or equal to distance |
Important Facts
- Distance is a scalar quantity.
- Displacement is a vector quantity.
- Distance is always positive.
- Displacement may be positive, negative, or zero.
- Distance can never be less than displacement.
- Displacement can be zero even when distance is not zero.
- If an object returns to its starting point, displacement becomes zero.
- Speed is based on distance, whereas velocity is based on displacement.
Quick Revision
- Distance measures the actual path travelled.
- Displacement measures the shortest path between two positions.
- Distance has magnitude only.
- Displacement has magnitude and direction.
- Distance is always greater than or equal to displacement.
- A complete round trip has zero displacement.
- Speed depends on distance.
- Velocity depends on displacement.
Quick Revision Fact: If a runner completes one full round of a circular track and returns to the starting point, the distance travelled equals the circumference of the track, but the displacement is zero.
Real-Life Examples of Speed and Velocity
The concepts of speed and velocity are not limited to textbooks and examination questions. We observe them in our daily lives whenever we travel, play sports, or watch moving vehicles. Understanding real-life examples helps students clearly distinguish between speed and velocity and makes the concepts easier to remember for competitive examinations.
Example 1: A Car Travelling on a Highway
Suppose a car is moving at 80 km/h on a highway.
- The value 80 km/h represents the speed of the car because it only tells how fast the car is moving.
- If we say the car is moving at 80 km/h towards Jammu, it represents velocity because direction has also been specified.
This example shows that velocity is simply speed along with direction.
Example 2: A Student Walking to School
A student walks from home to school, which is located 1 kilometre east of the house.
If the student covers this distance in 15 minutes:
- Speed tells how fast the student walked.
- Velocity tells how fast and in which direction the student walked.
If the student returns home after school:
- Total distance travelled = 2 km
- Displacement = 0 km
Therefore, the student has covered a distance but has zero displacement.
Example 3: A Train Moving Between Stations
A train travelling from Srinagar to Jammu at 70 km/h is an example of motion.
- 70 km/h indicates speed.
- 70 km/h towards Jammu indicates velocity.
Railway authorities use speed to determine travel time, while engineers often use velocity when direction is important.
Example 4: A Runner on a Circular Track
Consider an athlete running on a circular track.
After completing one full lap:
- Distance travelled equals the circumference of the track.
- Displacement becomes zero because the athlete returns to the starting point.
As a result:
- Average speed is not zero.
- Average velocity is zero.
This is one of the most common examples used in competitive examinations.
Example 5: An Airplane in Flight
Suppose an airplane flies at 900 km/h towards Delhi.
- 900 km/h represents speed.
- 900 km/h towards Delhi represents velocity.
Pilots and air traffic controllers must consider velocity because both speed and direction are important for navigation.
Example 6: A River Flowing Downstream
A river may flow at 5 m/s towards the south.
Since direction is specified, this is an example of velocity.
If only the value 5 m/s is mentioned without direction, it represents speed.
Example 7: A Bus in City Traffic
A bus moving through a crowded city road frequently accelerates, slows down, and changes direction.
Such motion is an example of:
- Non-uniform speed
- Variable velocity
The speed and velocity of the bus keep changing throughout the journey.
Example 8: A Lift (Elevator) Moving Upward
A lift moving upward at 2 m/s has:
- Speed = 2 m/s
- Velocity = 2 m/s upward
The moment the lift starts moving downward, the direction changes and so does its velocity.
Example 9: A Cricket Ball Thrown Upward
When a cricket ball is thrown vertically upward:
- Its speed decreases as it rises.
- At the highest point, its speed becomes zero.
- As it falls back, its speed increases again.
The velocity changes continuously because both the magnitude and direction of motion change during the journey.
Example 10: A Motorcycle Travelling on a Straight Road
A motorcycle moves 200 metres east in 10 seconds.
Distance = 200 metres
Displacement = 200 metres east
Since the motion is in a straight line without changing direction:
- Speed = 20 m/s
- Velocity = 20 m/s east
In such cases, the numerical values of speed and velocity are equal.
Everyday Situations Where Speed Is Used
Speed is commonly used in:
- Vehicle speedometers
- Sports competitions
- Road traffic regulations
- Railway schedules
- Flight timings
In most daily situations, people refer to speed rather than velocity because direction is not always required.
Everyday Situations Where Velocity Is Used
Velocity is important in:
- Aircraft navigation
- Space missions
- Weather forecasting
- Ship navigation
- River flow studies
- Engineering and physics calculations
In these fields, direction is as important as speed.
Speed and Velocity Around Us
| Situation | Speed or Velocity? |
| A car moving at 60 km/h | Speed |
| A car moving at 60 km/h north | Velocity |
| A train travelling at 90 km/h | Speed |
| A train travelling at 90 km/h towards Jammu | Velocity |
| A river flowing at 4 m/s south | Velocity |
| A cyclist moving at 15 km/h | Speed |
| An airplane flying at 800 km/h east | Velocity |
Key Points
- Speed tells only how fast an object moves.
- Velocity tells both speed and direction.
- Vehicle speedometers measure speed, not velocity.
- In a circular path, average velocity may become zero.
- If direction is specified, the quantity is usually velocity.
- Real-life applications help distinguish between speed and velocity.
Quick Revision
- Speed is used when only magnitude is important.
- Velocity is used when both magnitude and direction are important.
- A complete round trip has zero displacement.
- Speedometers measure speed.
- Pilots and navigators use velocity.
- An object can have speed without velocity, but velocity always includes speed.
Quick Revision Fact: Whenever direction words such as north, south, east, west, upward, or downward are mentioned, the quantity is usually velocity rather than speed.
SI Units
| Quantity | SI Unit |
| Distance | metre (m) |
| Displacement | metre (m) |
| Time | second (s) |
| Speed | metre per second (m/s) |
| Velocity | metre per second (m/s) |
Unit Conversion Formulas
Questions involving unit conversion are frequently asked in competitive examinations.
Conversion from km/h to m/s
m/s = (5/18) × km/h
Example:
72 km/h = 72 × 5/18 = 20 m/s
Conversion from m/s to km/h
km/h = (18/5) × m/s
Example:
20 m/s = 20 × 18/5 = 72 km/h
Most Important One-Liners
- Speed is the distance travelled per unit time.
- Velocity is the displacement covered per unit time.
- Speed is a scalar quantity.
- Velocity is a vector quantity.
- Speed has magnitude only.
- Velocity has both magnitude and direction.
- The SI unit of speed is m/s.
- The SI unit of velocity is m/s.
- Distance is always positive.
- Displacement can be positive, negative, or zero.
- Speed can never be negative.
- Velocity can be positive, negative, or zero.
- Speed depends on distance.
- Velocity depends on displacement.
- Distance is always greater than or equal to displacement.
- If displacement is zero, average velocity is zero.
- An object may have non-zero speed but zero velocity.
- Speedometer measures speed, not velocity.
- Uniform speed means equal distances in equal intervals of time.
- Uniform velocity means equal displacements in equal intervals of time in the same direction.
Frequently Asked Exam Facts
Can Speed Be Zero?
Yes. A stationary object has zero speed.
Can Velocity Be Zero?
Yes. If displacement is zero, velocity becomes zero.
Can Speed Be Negative?
No. Speed is always positive or zero.
Can Velocity Be Negative?
Yes. Velocity can be negative depending on the chosen direction.
When Are Speed and Velocity Equal?
When an object moves in a straight line without changing direction, distance becomes equal to displacement. In such cases, the numerical values of speed and velocity are equal.
Common Examination Traps
Students often make mistakes in the following situations:
- Using distance instead of displacement while calculating velocity.
- Ignoring direction in velocity questions.
- Confusing scalar and vector quantities.
- Forgetting unit conversions.
- Assuming speed and velocity are always the same.
Conclusion
Speed and velocity are two fundamental concepts used to describe the motion of an object. Although they appear similar, they differ in an important way. Speed tells us how fast an object is moving and is calculated using the distance travelled, whereas velocity tells us how fast and in which direction an object is moving and is calculated using displacement.
In this article, we learned that speed is a scalar quantity having only magnitude, while velocity is a vector quantity having both magnitude and direction. We also studied their formulas, SI units, types, numerical examples, real-life applications, and important differences. Understanding the concepts of distance and displacement is essential because they form the basis for distinguishing between speed and velocity.
For JKSSB Finance Accounts Assistant aspirants, this topic is important not only for theoretical questions but also for numerical and concept-based MCQs. Questions related to speed, velocity, displacement, average speed, average velocity, and circular motion are frequently asked in competitive examinations.
By mastering these concepts and practicing MCQs regularly, candidates can easily score marks from this topic in the JKSSB Finance Accounts Assistant examination and other competitive exams.
Remember: Whenever a question mentions only “how fast,” think of speed. Whenever a question mentions both “how fast” and “in which direction,” think of velocity.
Frequently Asked Questions (FAQs)
1. What is the difference between speed and velocity?
Speed is the distance travelled per unit time, whereas velocity is the displacement covered per unit time in a specific direction. Speed is a scalar quantity, while velocity is a vector quantity.
2. Is speed a scalar or vector quantity?
Speed is a scalar quantity because it has only magnitude and no direction.
3. Is velocity a scalar or vector quantity?
Velocity is a vector quantity because it has both magnitude and direction.
4. Can speed be negative?
No. Speed can never be negative because distance travelled is always positive or zero.
5. Can velocity be negative?
Yes. Velocity can be positive, negative, or zero depending on the direction of motion.
6. What is the SI unit of speed?
The SI unit of speed is metre per second (m/s).
7. What is the SI unit of velocity?
The SI unit of velocity is metre per second (m/s).
8. When are speed and velocity equal?
Speed and velocity are numerically equal when an object moves in a straight line without changing its direction. In such cases, distance equals displacement.
9. Why is velocity called a vector quantity?
Velocity is called a vector quantity because it requires both magnitude and direction for complete description.
10. What happens to velocity when displacement is zero?
When displacement is zero, average velocity also becomes zero, regardless of the distance travelled.
11. What is the formula for speed?
Speed = Distance ÷ Time
12. What is the formula for velocity?
Velocity = Displacement ÷ Time
13. Can an object have speed but no velocity?
No. If an object is moving, it has velocity. However, its average velocity can become zero if the total displacement is zero.
14. Which instrument measures the speed of a vehicle?
A speedometer is used to measure the speed of a vehicle.