CBSE Class 11 Physics Motion in a Straight Line Worksheet Set A

Question. In the displacement d versus time t graph given below, the value of average velocity in the time interval 0 to 20 s is (in m/s) 

(a) 1.5
(b) 4
(c) 1
(d) 2

Answer: C

Question. A body starts from rest and travels a distance x with uniform acceleration, then it travels a distance 2x with uniform speed, finally it travels a distance 3x with uniform retardation and comes to rest. If the complete motion of the particle is along a straight line, then the ratio of its average velocity to maximum velocity is
(a) 2/5
(b) 3/5
(c) 4/5
(d) 6/7

Answer: B

Question. A particle accelerates from rest at a constant rate for some time and attains a velocity of 8 m/sec. Afterwards it decelerates with the constant rate and comes to rest. If the total time taken is 4 sec, the distance travelled is
(a) 32 m
(b) 16 m
(c) 4 m
(d) None of the above

Answer: B

Question. The displacement x of a particle at the instant when its velocity is v is given by v = √3x +16 . Its acceleration and initial velocity are
(a) 1.5 units, 4 units
(b) 3 units, 4 units
(b) 16 units, 1.6 units
(d) 16 units, 3 units

Answer: A

Question. A ball is thrown vertically upward with a velocity ‘u’ from the balloon descending with velocity v. The ball will pass by the balloon after time
(a) u-v/2g
(b) u+v/2g
(c) 2(u-v)/g
(d) 2(u+v)/g

Answer: D

Question. Two bodies begin a free fall from the same height at a time interval of N s. If vertical separation between the two bodies is 1 after n second from the start of the first body, then n is equal to
(a) √nN
(b) 1/gN
(c) 1/gN + N/2
(d) 1/gN - N/4

Answer: C

Question. Which one of the following equations represents the motion of a body with finite constant acceleration ? In these equations, y denotes the displacement of the body at time t and a, b and c are constants of motion.
(a) y = at
(b) y = at + bt²
(c) y = at + bt² + ct³
(d) y = a/t + bt

Answer: B

Question. For the velocity time graph shown in the figure below the distance covered by the body in the last two seconds of its motion is what fraction of the total distance travelled by it in all the seven seconds? 

(a) 1/2
(b) 1/4
(c) 2/3
(d) 1/3

Answer: B

Question. A rocket is fired upward from the earth’s surface such that it creates an acceleration of 19.6 ms^-2 . If after 5 s, its engine is switched off, the maximum height of the rocket from earth’s surface would be
(a) 980 m
(b) 735 m
(c) 490 m
(d) 245 m

Answer: B

Question. The dependence of velocity of a body with time is given by the equation v = 20 + 0.1t². The body is in
(a) uniform retardation
(b) uniform acceleration
(c) non-uniform acceleration
(d) zero acceleration.

Answer: C

Question. A man leaves his house for a cycle ride. He comes back to his house after half-an-hour after covering a distance of one km. What is his average velocity for the ride ?
(a) zero
(b) 2 km h^–1
(c) 10 km s^–1
(d) 1/2 km s^-1

Answer: A

Question. The distance time graph of a particle at time t makes angles 45° with the time axis. After one second, it makes angle 60° with the time axis. What is the acceleration of the particle?
(a) √3 -1
(b) √3 +1
(c) √3
(d) 1

Answer: A 

Question. Two particles A and B are connected by a rigid rod AB. The rod slides along perpendicular rails as shown here. The velocity of A to the left is 10 m/s. What is the velocity of B when angle α = 60°? 

(a) 9.8 m/s
(b) 10 m/s
(c) 5.8 m/s
(d) 17.3 m/s

Answer: C

Question. The relation between time t and distance x is t = αx2 +βx where a and b are constants. The retardation is
(a) 2Vv³
(b) 2βv³
(c) 2αβv³
(d) 2β²v³

Answer: A

Question. A ball released from a height falls 5 m in one second. In 4 seconds it falls through
(a) 20 m
(b) 1.25 m
(c) 40 m
(d) 80 m

Answer: D

Question. A car travels from A to B at a speed of 20 km h^–1 and returns at a speed of 30 km h^–1. The average speed of the car for the whole journey is
(a) 5 km h^–1
(b) 24 km h^–1
(c) 25 km h^–1
(d) 50 km h^–1

Answer: B

Question. Two stones are thrown from the top of a tower, one straight down with an initial speed u and the second straight up with the same speed u. When the two stones hit the ground, they will have speeds in the ratio
(a) 2 : 3
(b) 2 : 1
(c) 1 : 2
(d) 1 : 1

Answer: D

Question. A parachutist after bailing out falls 50 m without friction. When parachute opens, it decelerates at 2 m/s² . He reaches the ground with a speed of 3 m/s. At what height, did he bail out ?
(a) 182 m
(b) 91 m
(c) 111 m
(d) 293 m

Answer: D

Question. A man throws balls with same speed vertically upwards one after the other at an interval of 2 sec. What should be the speed of throw so that more than two balls are in air at any time
(a) only with speed 19.6 m/s
(b) more than 19.6 m/s
(c) at least 9.8 m/s
(d) any speed less then 19.6 m/s.

Answer: B

Question. Let A, B, C, D be points on a vertical line such that AB = BC = CD. If a body is released from position A, the times of descent through AB, BC and CD are in the ratio.
(a) 1: √3 - √2 : √3 + √2
(b) 1: √2 -1: √3 - √2
(c) 1: √2 -1: √3
(d) 1: √2 : √3 -1

Answer: B

Question. When two bodies move uniformly towards each other, the distance decreases by 6 ms^–1. If both bodies move in the same directions with the same speeds (as above), the distance between them increases by 4 ms^–1. Then the speeds of the two bodies are
(a) 3 ms^–1 and 3 ms^–1
(b) 4 ms^–1 and 2 ms^–1
(c) 5 ms^–1 and 1 ms^–1
(d) 7 ms–1 and 3 ms–1

Answer: C

Question. A ball is dropped from a high rise platform at t = 0 starting from rest. After 6 seconds another ball is thrown downwards from the same platform with a speed v. The two balls meet at t = 18s. What is the value of v?
(take g = 10 m/s²)
(a) 75 m/s
(b) 55 m/s
(c) 40 m/s
(d) 60 m/s

Answer: A

Question. A particle moves a distance x in time t according to equation x = (t + 5)^–1. The acceleration of particle is proportional to
(a) (velocity)^3/2
(b) (distance)²
(c) (distance)^–2
(d) (velocity)²

Answer: A

Question. A particle has initial velocity (2i̅ + 3j̅) and acceleration (0.3i̅ + 0.2j̅). The magnitude of velocity after 10 seconds will be
(a) 9 √2 units
(b) 5 √2 units
(c) 5 units
(d) 9 units

Answer: B

Question. A car accelerates from rest at a constant rate a for some time after which it decelerates at a constant rate β to come to rest. If the total time elapsed is t, the maximum velocity acquired by the car is given by 

Answer: D