JEE Physics Motion In A Straight Line MCQs Set B

Question. Two balls are projected upward simultaneously with speeds 40 m/s and 60 m/s. Relative position (x) of second ball w.r.t. first ball at time t = 5 s is [Neglect air resistance].
(a) 100 m
(b) 120 m
(c) 80 m
(d) 20 m

Answer: A

Question. A train of 150 m length is going towards North at a speed of 10 m/s. A bird is flying at 5 m/s parallel to the track towards South. The time taken by the bird to cross the train is
(a) 10 s
(b) 15 s
(c) 30 s
(d) 12 s

Answer: A

Question. Two cars are moving in the same direction with a speed of 30 km/h. They are separated from each other by 5 km. Third car moving in the opposite direction meets the two cars after an interval of 4 minutes. The speed of the third car is
(a) 45 km/h
(b) 40 km/h
(c) 25 km/h
(d) 30 km/h

Answer: A

Question.  Two cars A and B are moving in same direction with velocities 30 m/s and 20 m/s. When car A is at a distance d behind the car B, the driver of the car A applies brakes producing uniform retardation of 2 m/s2. There will be no collision when
(a) d > 25 m
(b) d < 125 m
(c) d > 125 m
(d) d < 2.5 m

Answer: A

Question. Two trains each of length 100 m moving parallel towards each other at speed 72 km/h and 36 km/h respectively. In how much time will they cross each other?
(a) 6.67 s
(b) 3.5 s
(c) 7.25 s
(d) 4.5 s

Answer: A

Question. A ball is dropped from the top of a building of height 80 m. At same instant another ball is thrown upwards with speed 50 m/s from the bottom of the building. The time at which balls will meet is
(a) 1.6 s
(b) 5 s
(c) 8 s
(d) 10 s

Answer: A

Question. A ball is thrown upward with speed 10 m/s from the top of the tower reaches the ground with a speed 20 m/s. The height of the tower is [Take g = 10 m/s²]
(a) 15 m
(b) 20 m
(c) 10 m
(d) 25 m

Answer: A

Question. If magnitude of average speed and average velocity over an interval of time are same, then
(a) Particle must move in a straight line without turning back
(b) Particle must be at rest
(c) Particle must move with uniform acceleration
(d) Particle must move with zero acceleration

Answer: A

Question. A body is dropped from a certain height h (h is very large) and second body is thrown downward with velocity of 5 m/s simultaneouly. What will be difference in heights of the two bodies after 3s?
(a) 15 m
(b) 20 m
(c) 10 m
(d) 5 m

Answer: A

Question. Ball A is thrown up vertically with speed 10 m/s. At the same instant another ball B is released from rest at height h. At time t, the speed of A relative to B is
(a) 10 m/s
(b) 10 – 2 gt
(c) 10 – gt
(d) None of this

Answer: A

Question. A man moves in an open field such that after moving 10 m on a straight line, he makes a sharp turn of 60º to his left. The total displacement after 8 such turn is equal to
(a) 17.32 m
(b) 14.14 m
(c) 15 m
(d) 12 m

Answer: A

Question. A body starts from origin and moves along x-axis so that its position at any instant is x = 4t² – 12t where t is in second and v in m/s. What is the acceleration of particle?
(a) 8 m/s²
(b) 4 m/s²
(c) 24 m/s²
(d) 0 m/s²

Answer: A

Question. The motion of a particle along a straight line is described by equation  x = 8 + 12t – t³ where x is in metre and t in second. The retardation of the particle when its velocity becomes zero, is
(a) 12 ms^–2
(b) 24 ms^–2
(c) 6 ms^–2
(d) 8 ms–2

Answer: A

Question. A boy standing at the top of a tower of 20 m height drops a stone. Assuming g = 10 ms^–2, the velocity with which it hits the ground is
(a) 20.0 m/s
(b) 40.0 m/s
(c) 10.0 m/s
(d) 5.0 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^/3

Answer: A

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 = 18 s. What is the value of v? (Take g = 10 m/s²)
(a) 75 m/s
(b) 60 m/s
(c) 55 m/s
(d) 40 m/s

Answer: A

Question. The velocity of train increases uniformly from 20 km/h to 60 km/h in 4 hour. The distance travelled by the train during this period is
(a) 160 km
(b) 180 km
(c) 100 km
(d) 120 km

Answer: A

Question. A particle moves along a straight line suchthat its displacement at any time t is given bys = (t³ – 6t² – 3t + 4) metres. The velocity when the acceleration is zero is
(a) –15 m/s
(b) –9 m/s
(c) 42 m/s
(d) 3 m/s

Answer: A

Question. The water drops fall at regular intervals from a tap 5 m above the ground. The third drop is leaving the tap at instant the first drop touches the ground. How far above the ground is the second drop at that instant? (Take g = 10 ms^–2)
(a) 3.75 m
(b) 4. 00 m
(c) 1.25 m
(d) 2.50 m

Answer: A

Question. If a car at rest accelerates uniformly to a speed of144 km/h in 20 s, it covers a distance of
(a) 400 m
(b) 20 m
(c) 2980 cm
(d) 1440 cm

Answer: A

Question. A man throws balls with the same speed vertically upwards one after the other at an interval of 2 second. What should be the speed of the throw so that more than two balls are in the sky at any time? (Given g = 9.8 m/s²)
(a) More than 19.6 m/s
(b) Any speed less than 19.6 m/s
(c) At least 9.8 m/s
(d) Only with speed 19.6 m/s

Answer: A

Question.  A particle A is dropped from a height and another particle B is projected in horizontal direction with speed of 5 m/s from the same height then correct statement is
(a) Both particles will reach at ground simultaneously
(b) Both particles will reach at ground with same speed
(c) Particle B will reach at ground first with respect to particle A
(d) Particle A will reach at ground first with respect to particle B

Answer: A

Question. A particle is thrown vertically upward. Its velocity at half of the height is 10 m/s, then the maximum height attained by it is (g = 10 m/s²)
(a) 10 m
(b) 16 m
(c) 20 m
(d) 8 m

Answer: A

Question.  Motion of a particle is given by equation s = (3t³ + 7t² + 14t + 8) m The value of acceleration of the particle at t = 1 s is
(a) 32 m/s²
(b) 23 m/s²
(c) 16 m/s²
(d) 10 m/s²

Answer: A