NIOS Class 12 Physics Chapter 2 Motion in a Straight Line

NIOS Class 12 Physics Chapter 2 Motion in a Straight Line Solutions English Medium As Per New Syllabus to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Physics Chapter 2 Motion in a Straight Line Notes in English and select need one. NIOS Class 12 Physics Solutions English Medium Download PDF. NIOS Study Material of Class 12 Physics Notes Paper Code: 312.

NIOS Class 12 Physics Chapter 2 Motion in a Straight Line

Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Physics Notes, NIOS Senior Secondary Course Physics Solutions in English for All Chapter, You can practice these here.

Motion in a Straight Line

Chapter: 2

Module – I: Motion, Force and Energy

INTEXT QUESTIONS 2.1

1. Is it possible for a moving body to have non-zero average speed but zero average velocity during any given interval of time? If so, explain.

Ans: Yes, this is possible. Average velocity is the ratio of net displacement to total time, while average speed is the ratio of total distance traveled to total time.

Consider a body moving in a circular path and returning to its starting point. The total distance traveled is non-zero (circumference of the circle), but the net displacement is zero (as initial and final positions are the same).

Example: A car travels in a circular track of radius 100m and completes one full circle in 60s.

Distance traveled = 2πr 

= 2π(100) 

= 628.3 m

Average speed = 628.3/60 

= 10.47 m/s

Displacement = 0 

Average velocity = 0/60 

= 0 m/s

2. A lady drove to the market at a speed of 8 km h⁻¹. Finding market closed, she came back home at a speed of 10 km h⁻¹. If the market is 2km away from her home, calculate the average velocity and average speed.

Ans: Given: Distance to market = 2 km, 

Speed to market = 8 km h⁻¹, 

Speed back home = 10 km h⁻¹

Time to reach market: t₁ = 2/8 

= 0.25 h

Time to return home: t₂ = 2/10 

= 0.2 h

Total time = t₁ + t₂

= 0.25 + 0.2 

= 0.45 h

Average speed = Total distance/Total time

= (2 + 2)/0.45

= 4/0.45

= 8.89 km h⁻¹

Average velocity = Net displacement/Total time = 0/0.45 = 0 km h⁻¹
(Since she returns to her starting point, net displacement = 0)

3. Can a moving body have zero relative velocity with respect to another body? Give an example.

Ans: Yes, when two bodies move with the same velocity in the same direction, their relative velocity is zero.

Example: Two cars A and B traveling on a highway, both moving at 60 km h⁻¹ in the same direction.

Relative velocity of B with respect to A = vB – vA = 60 – 60 = 0 km h⁻¹

4. A person strolls inside a train with a velocity of 1.0 m s⁻¹ in the direction of motion of the train. If the train is moving with a velocity of 3.0 m s⁻¹, calculate his:

(a) velocity as seen by passengers in the compartment, and

(b) velocity with respect to a person sitting on the platform.

Ans: Given: Velocity of person relative to train = 1.0 m s⁻¹, 

Velocity of train = 3.0 m s⁻¹

(a) Velocity as seen by passengers in the compartment = 1.0 m s⁻¹

(This is the person’s velocity relative to the train)

(b) Velocity with respect to a person on the platform

= Velocity of person relative to train + Velocity of train

= 1.0 + 3.0 

= 4.0 m s⁻¹

INTEXT QUESTIONS 2.2

1. Draw the position-time graph for a motion with zero acceleration.

Ans: For zero acceleration, velocity is constant. Therefore, position increases linearly with time.

The position-time graph is a straight line with constant slope equal to the velocity.

[The graph would show a straight line with positive slope if moving in positive direction, horizontal line if at rest, or negative slope if moving in negative direction]

2. The following figure shows the displacement-time graph for two students A and B who start from their school and reach their homes. Look at the graphs carefully and Answer the following questions.

(i) Do they both leave school at the same time?

Ans: Yes, both graphs start from the origin (t = 0), indicating they leave school simultaneously.

(ii) Who stays farther from the school?

Ans: Student B stays farther from school, as the final displacement of B is greater than that of A.

(iii) Do they both reach their respective houses at the same time?

Ans: Yes, both graphs end at the same time value on the x-axis.

(iv) Who moves faster?

Ans: Student A moves faster. The slope of line A (Δx/Δt) is steeper than that of line 

B, indicating higher average velocity.

(v) At what distance from the school do they cross each other?

Ans: They cross where the two lines intersect on the graph. Reading from the intersection point, this occurs at the displacement value where both lines meet.