Ready to test your Physics skills? Try this TNPSC Physics online MCQ test on Equations of Motion and see how well you can apply the formulas. The questions cover the first, second, and third equations of motion, initial and final velocity, displacement, time, acceleration, and uniformly accelerated motion. You’ll also get questions on SI units, velocity-time and distance-time graphs, slope, area under graphs, and other motion-based concepts from the TNPSC General Science syllabus. Give it a try and find out how confidently you can solve these questions!
Note: Your preparation does not end with the test. Detailed explanations are provided below to help you learn from every question
Choose the next test, revise the complete Motion chapter, or reading the detailed explanations.
TNPSC Physics – Motion Test 5 (Equations of Motion) – Topic Overview & Quick Revision
The questions in this TNPSC Physics test 5 focus on how the Equations of Motion are used to describe the movement of objects. The section covers the first, second, and third equations of motion along with initial velocity, final velocity, displacement, time, acceleration, and uniformly accelerated motion. It also looks at SI units and the use of velocity-time and distance-time graphs, including their slope and area. Use these explanations to review the important ideas behind each question and strengthen your preparation for the TNPSC General Science syllabus.
1. The first equation of motion relates
✔ Correct Answer: B. Velocity, acceleration, and time
Explanation:
The first equation of motion is v = u + at. It describes the relationship between the initial velocity (u), final velocity (v), acceleration (a), and time (t) when an object moves with uniform acceleration. It is useful for finding the final velocity when the initial velocity, acceleration, and time are known.
Key Points:
- First equation of motion: v = u + at
- u = initial velocity
- v = final velocity
- a = acceleration
- t = time
- It applies to uniformly accelerated motion.
Real-Life Example: When a car starts from rest and accelerates uniformly, its velocity increases with time. The first equation of motion can be used to calculate its velocity after a certain period.
2. Which of the following is the first equation of motion?
✔ Correct Answer: C. v = u + at
Explanation:
The first equation of motion is v = u + at, which connects an object’s initial velocity, final velocity, acceleration, and time. The other equations have different purposes: s = ut + ½at² is the second equation of motion, while v² = u² + 2as is the third equation. F = ma is Newton’s second law of motion, not an equation of motion.
Key Points:
- First equation: v = u + at
- Second equation: s = ut + ½at²
- Third equation: v² = u² + 2as
- F = ma represents Newton’s second law.
- Equations of motion are used for uniformly accelerated motion.
Real-Life Example: If a bicycle increases its speed at a uniform rate, v = u + at can be used to determine its final velocity after a given time.
3. Which of the following is the second equation of motion?
Answer: A. s = ut + ½at²
Explanation:
The second equation of motion is s = ut + ½at². It gives the displacement covered by an object moving with uniform acceleration during a given time. The equation considers the initial velocity, acceleration, and time to determine the displacement.
Key Points:
- Second equation of motion: s = ut + ½at²
- s represents displacement.
- u represents initial velocity.
- a represents acceleration.
- t represents time.
- It applies to uniformly accelerated motion.
Real-Life Example: If a car moves with uniform acceleration, this equation can be used to calculate how far it travels during a particular time interval.
4. Which of the following is the third equation of motion?
Answer: C. v² = u² + 2as
Explanation:
The third equation of motion is v² = u² + 2as. It establishes a relationship between the initial velocity, final velocity, acceleration, and displacement of an object undergoing uniform acceleration. Unlike the first and second equations, this equation does not involve time.
Key Points:
- Third equation of motion: v² = u² + 2as
- u represents initial velocity.
- v represents final velocity.
- a represents acceleration.
- s represents displacement.
- Time is not included in this equation.
Real-Life Example: When studying a vehicle accelerating along a straight road, this equation can be used to determine its final velocity when the acceleration and distance travelled are known.
5. In the equation v = u + at, the symbol u represents
Answer: B. Initial velocity
Explanation:
In the first equation of motion, v = u + at, the symbol u represents the initial velocity of the object. It is the velocity of the object at the beginning of the time interval being considered. Knowing the initial velocity along with acceleration and time helps determine the final velocity.
Key Points:
- u represents initial velocity.
- v represents final velocity.
- a represents acceleration.
- t represents time.
- The first equation of motion is v = u + at.
Real-Life Example: If a cyclist is already moving at a certain speed before starting to accelerate, that speed is the initial velocity represented by u.
6. In the equation v = u + at, the symbol v represents
Answer: C. Final velocity
Explanation:
In the first equation of motion, v = u + at, the symbol v represents the final velocity of the object after the specified time interval. It can be calculated when the initial velocity, acceleration, and time are known.
Key Points:
- v represents final velocity.
- u represents initial velocity.
- Acceleration changes the velocity of the object.
- The equation v = u + at applies to uniformly accelerated motion.
Real-Life Example: When a car accelerates from an initial speed, the speed it reaches after a certain period is its final velocity.
7. The equations of motion are valid only for
Answer: B. Uniformly accelerated motion
Explanation:
The equations of motion are used to describe the motion of an object when its acceleration remains constant during the time interval considered. This is known as uniformly accelerated motion. If acceleration changes continuously, these simple equations cannot be directly applied.
Key Points:
- Equations of motion apply to uniformly accelerated motion.
- Uniform acceleration means acceleration remains constant.
- The three equations are v = u + at, s = ut + ½at², and v² = u² + 2as.
- These equations are commonly used to solve problems involving velocity, displacement, time, and acceleration.
Real-Life Example: An object falling freely near the Earth’s surface can be treated as having nearly constant acceleration due to gravity when air resistance is neglected.
8. Which quantity is measured in m/s²?
Answer: C. Acceleration
Explanation:
Acceleration is the rate at which velocity changes with time. Its SI unit is metre per second squared (m/s²). This means that the velocity changes by a certain number of metres per second for every second of time.
Key Points:
- SI unit of acceleration: m/s²
- Acceleration describes the change in velocity with time.
- Velocity is measured in m/s.
- Time is measured in seconds.
- Displacement is measured in metres.
Real-Life Example: When a car increases its speed, its velocity changes with time. The rate of this change is its acceleration.
9. If acceleration is zero, the equation v = u + at becomes
Answer: B. v = u
Explanation:
The first equation of motion is v = u + at. When acceleration is zero, the term at also becomes zero. Therefore, the equation reduces to v = u, which means the final velocity is equal to the initial velocity. In this situation, the object continues with constant velocity if no other condition changes its motion.
Key Points:
- First equation of motion: v = u + at
- When a = 0, the acceleration term becomes zero.
- Therefore, v = u.
- The velocity remains constant when acceleration is zero.
Real-Life Example: A car travelling along a straight road at a constant speed has zero acceleration, provided its direction also remains unchanged.
10. Which graph is used to determine acceleration from its slope?
Answer: B. Velocity-time graph
Explanation:
The slope of a velocity-time graph represents acceleration. It is found by dividing the change in velocity by the corresponding change in time. Therefore, a velocity-time graph can be used to determine the acceleration of a moving object.
Key Points:
- Slope of velocity-time graph = acceleration.
- Acceleration is the change in velocity with time.
- A steeper slope indicates greater acceleration.
- Zero slope indicates zero acceleration.
Real-Life Example: When a runner increases their speed during a race, a velocity-time graph can show how quickly their velocity is changing.
11. The area under a velocity-time graph represents
Answer: C. Displacement
Explanation:
The area under a velocity-time graph represents the displacement of an object during the given time interval. This is because velocity multiplied by time gives displacement when the velocity is constant, and the area under the graph extends this idea to changing velocity.
Key Points:
- Area under a velocity-time graph = displacement.
- Displacement is measured in metres.
- The time interval is shown along the horizontal axis.
- Velocity is shown along the vertical axis.
Real-Life Example: A train moving along a track can have its displacement over a particular time interval determined from the area under its velocity-time graph.
12. A straight line in a velocity-time graph indicates
Answer: B. Uniform acceleration
Explanation:
A straight line on a velocity-time graph means that velocity changes at a constant rate with time. This indicates uniform acceleration. The slope of the straight line gives the value of the acceleration.
Key Points:
- Straight-line velocity-time graph → uniform acceleration.
- Slope of the graph gives acceleration.
- A horizontal straight line indicates constant velocity.
- A changing slope indicates changing acceleration.
Real-Life Example: A ball rolling down a smooth inclined surface with approximately constant acceleration can be represented by a straight-line velocity-time graph.
13. Which of the following quantities is a vector?
Answer: D. Acceleration
Explanation:
Acceleration is a vector quantity because it has both magnitude and direction. It describes how quickly the velocity of an object changes with time. The direction of acceleration is important when describing changes in the motion of an object.
Key Points:
- Acceleration is a vector quantity.
- A vector has both magnitude and direction.
- Speed, distance, and time are scalar quantities.
- The SI unit of acceleration is m/s².
Real-Life Example: When a ball is thrown upward, its acceleration due to gravity acts downward throughout its motion.
14. The slope of a distance-time graph represents
Answer: B. Speed
Explanation:
The slope of a distance-time graph gives the speed of an object. It is calculated by dividing the change in distance by the corresponding change in time. A steeper slope indicates that the object is moving faster.
Key Points:
- Slope of distance-time graph = speed.
- Speed = distance ÷ time.
- A steeper slope indicates greater speed.
- Distance-time graphs use distance on the vertical axis and time on the horizontal axis.
Real-Life Example: A cyclist covering more distance in the same amount of time has a greater speed, which is represented by a steeper slope on a distance-time graph.
15. Which equation of motion does not contain time?
Answer: C. v² = u² + 2as
Explanation:
The third equation of motion, v² = u² + 2as, does not contain the time variable. It relates the initial velocity, final velocity, acceleration, and displacement. This equation is particularly useful when the time taken for the motion is not known or is not required.
Key Points:
- Third equation: v² = u² + 2as
- It does not contain time.
- u = initial velocity.
- v = final velocity.
- a = acceleration.
- s = displacement.
Real-Life Example: When an object moves down an inclined surface, the third equation can be used to find its final velocity if its initial velocity, acceleration, and displacement are known.
16. Which quantity is represented by the symbol s?
Answer: B. Displacement
Explanation:
In the equations of motion, the symbol s represents the displacement of an object during the motion being considered. Displacement refers to the change in position of an object from its initial position to its final position and is measured in metres.
Key Points:
- s represents displacement.
- Displacement is a vector quantity.
- The SI unit of displacement is metre (m).
- The symbol s is used in the second and third equations of motion.
Real-Life Example: If a person walks from one point to another, the change in their position from the starting point to the ending point represents displacement.
17. The equations of motion are derived using
Recommended correction: Change option A to Basic kinematic relationships.
Answer: A. Basic kinematic relationships
Explanation:
The equations of motion are obtained from basic relationships between displacement, velocity, acceleration, and time for uniformly accelerated motion. These relationships lead to the three standard equations used to solve problems involving the motion of an object.
Key Points:
- Equations of motion describe uniformly accelerated motion.
- They relate velocity, acceleration, displacement, and time.
- There are three commonly used equations of motion.
- They are based on basic kinematic relationships.
Real-Life Example: The motion of an object sliding down a smooth inclined surface can be analysed using these relationships when its acceleration is considered uniform.
18. Which of the following is an example of uniformly accelerated motion?
Answer: A. A freely falling body near the Earth’s surface
Explanation:
A freely falling body near the Earth’s surface undergoes approximately constant acceleration due to gravity when air resistance is neglected. Since its velocity changes at a nearly constant rate, it is considered an example of uniformly accelerated motion.
Key Points:
- Free fall is an example of uniformly accelerated motion.
- Acceleration due to gravity is approximately constant near the Earth’s surface.
- The approximate value of g is 9.8 m/s².
- Air resistance is usually neglected when considering ideal free fall.
Real-Life Example: A stone released from a height falls towards the ground with approximately constant acceleration due to gravity.
19. The symbol t in the equations of motion represents
Answer: B. Time
Explanation:
In the equations of motion, the symbol t represents the time interval during which the motion takes place. Time is used along with initial velocity and acceleration to determine quantities such as final velocity and displacement.
Key Points:
- t represents time.
- The SI unit of time is second (s).
- Time is included in the first and second equations of motion.
- Time is not included in the third equation of motion.
Real-Life Example: When measuring how long a runner takes to complete a particular distance, the duration recorded is represented by t in motion calculations.
20. Which statement is correct regarding the equations of motion?
Answer: B. They are applicable only for uniformly accelerated motion.
Explanation:
The equations of motion are used when an object moves with uniform acceleration, meaning its acceleration remains constant during the time interval considered. They establish relationships between velocity, displacement, acceleration, and time and are commonly used to solve problems involving uniformly accelerated motion.
Key Points:
- Equations of motion apply to uniformly accelerated motion.
- Uniform acceleration means constant acceleration.
- The three equations relate velocity, displacement, acceleration, and time.
- They cannot be directly applied when acceleration varies continuously.
Real-Life Example: A freely falling object near the Earth’s surface can be treated as uniformly accelerated when air resistance is neglected.
Quick Revision – All Test 5 Questions
- First equation of motion: v = u + at
- Second equation of motion: s = ut + ½at²
- Third equation of motion: v² = u² + 2as
- u = initial velocity; v = final velocity.
- s = displacement; t = time; a = acceleration.
- Equations of motion apply to uniformly accelerated motion.
- SI unit of acceleration is m/s².
- When acceleration is zero, v = u, so velocity remains constant.
- Slope of a velocity-time graph gives acceleration.
- Area under a velocity-time graph gives displacement.
- A straight-line velocity-time graph represents uniform acceleration when its slope is constant.
- Slope of a distance-time graph gives speed.
- Acceleration is a vector quantity; speed, distance, and time are scalar quantities.
- The third equation of motion does not contain time.
- The equations of motion are based on basic kinematic relationships.
- A freely falling body near Earth’s surface is an example of approximately uniformly accelerated motion when air resistance is neglected.
- The three equations connect velocity, displacement, acceleration, and time for uniformly accelerated motion.
Further Reference Material For Topic “Motion”
For additional study on Equations of Motion, refer to the NCERT chapter Describing Motion Around Us. It provides useful explanations of displacement, velocity, acceleration, equations of motion, and motion graphs, making it a helpful reference for revising the Physics concepts covered in this TNPSC Physics test.
