Question

29. A train starts from station with an acceleration 1 m/s?. A boy who is 48 m behind the train with
a constant velocity 10 m/s, the minimum time after which the boy will catch the train is :
(A) 4.8 sec
(B) 8 sec
(C) 10 sec
(D) 12 sec
30. A particle moves 200 cm in the first 2 sec and 220 cm in the next 4 sec with uniform
deceleration. The velocity of the particle at the end of seven second is :
(A) 15 cm/s
(B) 20 cm/s
(C) 10 cm/s
(D) none of these
31. An aeroplane flying horizontally with speed 90 km/hr releases a bomb at a height of 78.4 m
from the ground, when will the bomb strike the ground ?
(A) 8 sec
(B) 6 sec
(C) 4 sec
(D) 10 sec
32. A stone is projected upwards and it returns to ground on a parabolic path. Which of the
following remains constant ?
(A) Speed of the ball
(B) Horizontal component of velocity
(C) Vertical component of velocity
(D) None of the above
33. A stone is released from the top of a tower. The total distance covered by it in the last second
of its motion equals distance covered by it in the first three seconds of its motion. The stone
remains in the air for :
(A) 5 sec
(B) 8 sec
(C) 10 sec
(D) 15 sec
34. A ball of mass M is thrown vertically upwards. Another ball of mass 2M is thrown at an angle
O to vertical. Both of them stay in air for the same period of time, the heights attained by
the two are in the ratio :
(A) 1:2
(B) 2:1
(C)1:1
(D) 1: cose
An aeronlane is flying horizontally with velocity 150 m/s at a height 100 m from the ground.
25​

Answer 1

Answer: 8s

Explanation:

v2= U2+2as

v2 = 2*1*48

v= 4√6

Vrel.= 10-4√6= 6√6

t= d/6√6

= 48/6√6

t=8s