Participate in 11th Physics Motion in a Straight Line MCQ Chapter Quiz** Quiz** for check knowledge with instant result for all type board exam, competitive exam like IIT JEE and other engineering entrance exam. You can also participate in **Physics Quiz Contest every month** as well as **yearly math quiz competition** on official international QuizRanker website.

## Motion in a Straight Line MCQ Test

**Study Quiz Motion in a Straight Line Question Answer**

### Score card of Motion in a Straight Line Mock Test

Pos. | Name | Score | Points |
---|---|---|---|

There is no data yet |

QuizRanker.org is a reputable and free academic website where you can access authentic 11th-grade physics multiple-choice questions (MCQs) chapter wise like **Class 12 Physics Motion in a Straight Line MCQ Quiz** **Part**. Engage in **eleventh physics monthly quiz contests** to assess your standing at no cost. Achieving high scores on a monthly basis will not only boost your positivity but also qualify you to participate in the **International annual quiz competition scheduled for December 2024**. Take a deep breath, stay positive, and make the most of this opportunity to enhance your academic prowess.

## Motion in a Straight Line NCERT Question Answers

**Q**2.1 In which of the following examples of motion, can the body be considered approximately a point object:

(a) a railway carriage moving without jerks between two stations.

(b) a monkey sitting on top of a man cycling smoothly on a circular track.

(c) a spinning cricket ball that turns sharply on hitting the ground.

(d) a tumbling beaker that has slipped off the edge of a table.

**Ans: (a), (b)**

**Q**2.2 The position-time (x-t) graphs for two children A and B returning from their school O to their homes P and Q respectively are shown in Fig. 2.9. Choose the correct entries in the brackets below ;

(a) (A/B) lives closer to the school than (B/A)

(b) (A/B) starts from the school earlier than (B/A)

(c) (A/B) walks faster than (B/A)

(d) A and B reach home at the (same/different) time

(e) (A/B) overtakes (B/A) on the road (once/twice).

**Ans:** (a) A….B, (b) A….B, (c) B….A, (d) Same, (e) B….A….once.

**Q**2.3 A woman starts from her home at 9.00 am, walks with a speed of 5 km h–1 on a straight road up to her office 2.5 km away, stays at the office up to 5.00 pm, and returns home by an auto with a speed of 25 km h–1. Choose suitable scales and plot the x-t graph of her motion.

**Ans: **

Speed of the woman = 5 km/h

Distance between her office and home = 2.5 km

Time taken = Distance / Speed

= 2.5 / 5 = 0.5 h = 30 min

It is given that she covers the same distance in the evening by an auto.

Now, speed of the auto =25 km/h

Time taken = Distance / Speed

= 2.5/25=1/10=0.1h=6 min

The suitable *x*–*t* graph of the motion of the woman is shown in the given figure.

**Q**2.4 A drunkard walking in a narrow lane takes 5 steps forward and 3 steps backward, followed again by 5 steps forward and 3 steps backward, and so on. Each step is 1 m long and requires 1 s. Plot the x-t graph of his motion. Determine graphically and otherwise how long the drunkard takes to fall in a pit 13 m away from the start.

Ans: 37 s

2.5 A car moving along a straight highway with speed of 126 km h–1 is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop ?

Ans: 3.06 m s–2 ; 11.4 s

**Q**2.6 A player throws a ball upwards with an initial speed of 29.4 m s–1.

(a) What is the direction of acceleration during the upward motion of the ball ?

(b) What are the velocity and acceleration of the ball at the highest point of its motion ?

(c) Choose the x = 0 m and t = 0 s to be the location and time of the ball at its highest point, vertically downward direction to be the positive direction of x-axis, and give the signs of position, velocity and acceleration of the ball during its upward, and downward motion.

(d) To what height does the ball rise and after how long does the ball return to the player’s hands ? (Take g = 9.8 m s–2 and neglect air resistance).

**Ans:**

(a) Vertically downwards; (b) zero velocity, acceleration of 9.8 m s-2 downwards;

(c) x > 0 (upward and downward motion); v < 0 (upward), v > 0 (downward), a > 0

throughout; (d) 44.1 m, 6 s.

2.7 Read each statement below carefully and state with reasons and examples, if it is true or false ;

A particle in one-dimensional motion

(a) with zero speed at an instant may have non-zero acceleration at that instant

(b) with zero speed may have non-zero velocity,

(c) with constant speed must have zero acceleration,

(d) with positive value of acceleration must be speeding up.

Ans: (a) True;, (b) False; (c) True (if the particle rebounds instantly with the same speed, it

implies infinite acceleration which is unphysical); (d) False (true only when the chosen

positive direction is along the direction of motion)

2.8 A ball is dropped from a height of 90 m on a floor. At each collision with the floor, the ball loses one tenth of its speed. Plot the speed-time graph of its motion between t = 0 to 12 s.

2.9 Explain clearly, with examples, the distinction between :

(a) magnitude of displacement (sometimes called distance) over an interval of time, and the total length of path covered by a particle over the same interval;

(b) magnitude of average velocity over an interval of time, and the average speed over the same interval. [Average speed of a particle over an interval of time is defined as the total path length divided by the time interval]. Show in both (a) and (b) that the second quantity is either greater than or equal to

the first. When is the equality sign true ? [For simplicity, consider one-dimensional motion only].

2.10 A man walks on a straight road from his home to a market 2.5 km away with

a speed of 5 km h–1. Finding the market closed, he instantly turns and walks back home with a speed of 7.5 km h–1. What is the

(a) magnitude of average velocity, and

(b) average speed of the man over the interval of time (i) 0 to 30 min, (ii) 0 to 50 min, (iii) 0 to 40 min ?

[Note: You will appreciate from this exercise why it is better to define average speed as total path length divided by time, and not as magnitude of average velocity. You would not like to tell the tired man on his return home that his average speed was zero !]

**Ans: **

2.11 In Exercises 2.9 and 2.10, we have carefully distinguished between average speed and magnitude of average

velocity. No such distinction is necessary when we consider instantaneous speed and magnitude of velocity. The instantaneous speed is always equal to the magnitude of instantaneous velocity. Why?

**Ans:** Because, for an arbitrarily small interval of time, the magnitude of displacement is equal to the length of the path.

2.12 Look at the graphs (a) to (d) (Fig. 2.10) carefully and state, with reasons, which of these cannot possibly represent one-dimensional motion of a particle.

Ans: All the four graphs are impossible. (a) a particle cannot have two different positions at the same time; (b) a particle cannot have velocity in opposite directions at the same time; (c) speed is always non-negative; (d) total path length of a particle can never decrease with time. (Note, the arrows on the graphs are meaningless).

2.13 Figure 2.11 shows the x-t plot of onedimensional motion of a particle. Is it correct to say from the graph that the particle moves in a straight line for t < 0 and on a parabolic path for t >0 ? If not, suggest a suitable physical

context for this graph.

**Ans: **No, wrong. x-t plot does not show the trajectory of a particle. Context: A body is dropped

from a tower (x = 0) at t = 0.

2.14 A police van moving on a highway with a speed of 30 km h–1 fires a bullet at a thief’s car speeding away in

the same direction with a speed of 192 km h–1. If the muzzle speed of the bullet is 150 m s–1, with what speed oes the bullet hit the thief’s car ? (Note: Obtain that speed which is relevant for damaging the thief’s car).

**Ans:** 105 m s-1

2.15 Suggest a suitable physical situation for each of the following graphs (Fig 2.12):

**Ans: **(a) A ball at rest on a smooth floor is kicked, it rebounds from a wall with reduced speed and moves to the opposite wall which stops it; (b) A ball thrown up with some initial velocity rebounding from the floor with reduced speed after each hit; (c) A uniformly moving cricket ball turned back by hitting it with a bat for a very short time-interval.

**Q**2.16 Figure 2.13 gives the x-t plot of a particle executing one-dimensional simple harmonic motion. (You will learn about this motion in more detail in Chapter13). Give the signs of position, velocity and acceleration variables of the particle at t = 0.3 s, 1.2 s, – 1.2 s.

**Ans:** x < 0, v < 0, a > 0; x > 0, v > 0, a < 0; x < 0, v > 0, a > 0.

**Q**2.17 Figure 2.14 gives the x-t plot of a particle in one-dimensional motion. Three different equal intervals of time

are shown. In which interval is the average speed greatest, and in which is it the least ? Give the sign of average velocity for each interval.

**Ans: **Greatest in 3, least in 2; v > 0 in 1 and 2, v < 0 in 3.

Q2.18. Figure 2.15 gives a speed-time graph of a particle in motion along a constant direction. Three equal intervals of time are shown. In which interval is the average acceleration greatest in magnitude? In which interval is the average speed greatest ? Choosing the positive direction as the constant direction of motion, give the signs of v and a in the three intervals. What are the accelerations at the points A, B, C and D ?

**Ans:** Acceleration magnitude greatest in 2; speed greatest in 3; v > 0 in 1, 2 and 3; a > 0 in 1 and 3, a < 0 in 2; a = 0 at A, B, C, D.

**Chapter wise quiz of 11th class Physics MCQ**

Chapter 1 Units and Measurements MCQ and NCERT Question Answer

1.1 Introduction

1.2 The international system of units

1.3 Significant figures

1.4 Dimensions of physical quantities

1.5 Dimensional formulae and dimensional equations

1.6 Dimensional analysis and its applications

Chapter 2 Motion in A Straight Line MCQ and NCERT Question Answer

2.1 Introduction

2.2 Instantaneous velocity and speed

2.3 Acceleration

2.4 Kinematic equations for uniformly accelerated motion

Chapter 3 Motion In A Plane MCQ and NCERT Question Answer

3.1 Introduction

3.2 Scalars and vectors

3.3 Multiplication of vectors by real numbers

3.4 Addition and subtraction of vectors – graphical method

3.5 Resolution of vectors

3.6 Vector addition – analytical method

3.7 Motion in a plane

3.8 Motion in a plane with constant acceleration

3.9 Projectile motion

3.10 Uniform circular motion

Chapter 4 Laws of Motion MCQ and NCERT Question Answer

4.1 Introduction

4.2 Aristotle’s fallacy

4.3 The law of inertia

4.4 Newton’s first law of motion

4.5 Newton’s second law of motion

4.6 Newton’s third law of motion

4.7 Conservation of momentum

4.8 Equilibrium of a particle

4.9 Common forces in mechanics

4.10 Circular motion

4.11 Solving problems in mechanics

Chapter 5 Work, Energy and Power MCQ and NCERT Question Answer

5.1 Introduction

5.2 Notions of work and kinetic energy : The work-energy theorem

5.3 Work

5.4 Kinetic energy

5.5 Work done by a variable force

5.6 The work-energy theorem for a variable force

5.7 The concept of potential energy

5.8 The conservation of mechanical energy

5.9 The potential energy of a spring

5.10 Power

5.11 Collisions

Chapter 6 System Of Particles And Rotational Motion MCQ and NCERT Question Answer

6.1 Introduction

6.2 Centre of mass

6.3 Motion of centre of mass

6.4 Linear momentum of a system of particles

6.5 Vector product of two vectors

6.6 Angular velocity and its relation with linear velocity

6.7 Torque and angular momentum

6.8 Equilibrium of a rigid body

6.9 Moment of inertia

6.10 Kinematics of rotational motion about a fixed axis

6.11 Dynamics of rotational motion about a fixed axis

6.12 Angular momentum in case of rotations about a fixed axis

Chapter 7 Gravitation MCQ and NCERT Question Answer

7.1 Introduction

7.2 Kepler’s laws

7.3 Universal law of gravitation

7.4 The gravitational constant

7.5 Acceleration due to gravity of the earth

7.6 Acceleration due to gravity below and above the surface of earth

7.7 Gravitational potential energy

7.8 Escape speed

7.9 Earth satellites

7.10 Energy of an orbiting satellite