G-MS2D75B7RR

# Worksheet on Motion In A Straight Line

Q1 A car travels a distance d on a straight road in two hours and then returns to the starting point in next three hours. Its average speed is :

a) d/5

b) 2d/5

c) d/2 + d/3

d) none of these

Q2.A car moving on a straight road covers one third of a certain distance with 20 km/h and the rest with 60km/h. The average speed is :

a) 40 km/h

b) 80 km/h

c) 46 2/3 km/h

d) 36 km/h

Q3.If displacement of a particle is zero, the distance covered

a) must be zero

b) may or may not be zero

c) cannot be zero

d) depends upon the particle

Q4. If the distance covered is zero, the displacement

a) must be zero

b) may or may not be zero

c) cannot be zero

d) depends upon the particle

Q5 A car runs at constant speed on a circular track of radius 10m taking 6.28s on each lap (i.e. round). The average speed and average velocity for each complete lap is

a) Velocity 10 m/s, speed 10 m/s

b) Velocity zero, speed 10 m/so

c) Velocity zero, speed zero

d) Velocity 10 m/s speed zero

Q6 The location of a particle is changed. What can we say about the displacement and distance covered by the particle :

a) Both cannot be zero

b) One of the two may be zero

c) Both must be zero

d) If one is positive, the other is negative and vice-versa

Q7 Select the incorrect statements from the following.

S1 : Average velocity is path length divided by time interval.

S2. In general, average speed is greater than the magnitude of the average velocity

S3. A particle moving in a given direction with a non-zero velocity can have zero speed.

S4. The magnitude of average velocity is the average speed.

a) S2 and S3

b) S1 and S4

c) S1, S3 and S4

d) All four statements

Q8 If a car at rest accelerates uniformly and attains a speed of 72 km/h in 10s. then it covers a distance of

a) 50 m

b) 100 m

c) 60 m

d) 180m

Q9 If a ball is thrown vertically upwards with 40 m/s. its velocity after two seconds will be :

a) 10 m/s

b) 20 m/s

c) 30 m/s

d) 40 m/s

Q10 A body dropped from a tower reaches the ground in 4s. The height of tower is about :

a) 80 m

b) 20 m

c) 160 m

d) 40m

Q11 A ball is thrown upward with a velocity of 100 m/s. It will each the ground after :-

a) 10 s

b) 20 s

c) 5 s

d) 40 s

Q12 A body starts from rest. What is the ratio of the distance travelled by the body during the 4th and 3rd second ?

a) 7/5

b) 5/7

c) 7/3

d) 3/7

Q13 A stone is thrown upwards and it rises to a height of 200 m. The relative velocity of the stone with respect to the earth will be maximum at :-

a) Height of 100 m

b) Height of 150m

c) Highest point

d) The ground

Q14 A boy standing at the top a tower of 20 m height drops a stone. Assuming g = 10 m/s square, the velocity with which it hits the ground is :-

a) 10.0 m/s

b) 20.0 m/s

c) 40.0 m/s

d) 5.0 m/s

Q15 A particle travels 10m in first 5 seconds and 10m in next 3 seconds. Assuming constant acceleration, what is the distance travelled in next 2 second ?

a) 8.3 m

b) 9.3 m

c) 10.3 m

d) None of these

Q16 A balloon rises from the ground with an acceleration of 1.25 m per sec square. After 8s, a stone is released from the balloon. The stone will - (taking g = 10 m per sec square )

a) have a displacement of 50 m

b) cover a distance of 40m in reaching the ground

c) reach the ground in 4s

d) begin to move downwards after being released

Q17 A man walks on a straight road from his home to a market 2.5 km away with a speed of 5 km/h. Finding the market closed, he instantly turns and walks back home with a speed of 7.5 km/h. The average speed of the man over the interval of the 0 to 40 min is equal to.

a) 5 km/h

b) 25/4 km/h

c) 30/4 km/h

d) 45/8 km/h

Q18 Assertion :- A body can have acceleration even if its velocity is zero at a given instant of time.

Reason :- A body is momentarily at rest when it reverses its direction of motion.

a) A

b) B

c) C

d) D

Q19 Assertion :- If the displacement of the body is zero, the distance covered by it may not be zero.

Reason :- Displacement depends only on end points ; distance (path length) depends on the actual path.

a) A

b) B

c) C

d) D

Q20 Assertion :- An object can have constant speed but variable velocity.

Reason :- Speed is a scalar but velocity is a vector quantity.

a) A

b) B

c) C

d) D

Q21Two buses start simultaneously towards each other from towns A and B which are 480 km apart. The first bus takes 8 hours to travel from A to B while the second bus takes 12 hours to travel from B to A. Determine when buses will meet.

a) 2.8 h

b) 3.8 h

c) 4.8 h

d) 5.8 h

Q22 What is the importance of frame of reference?

Q23) What is the shape of trajectory of an object moving under constant acceleration?

1) b

2) d

3) b

4) a

5) b

6) a

7) c

8) b

9) b

10) a

11) b

12) a

13) d

14) b

15) a

16) c

17) d

18) a

19) a

20) a

21) c

22) Motion/rest is always relative to the observer. There is no meaning of rest or motion without the observer or frame of reference.

23) The trajectory of an object moving under constant acceleration can be straight line or parabola.