CBSE
Multiple Choice QuestionsA ball is dropped from a tower of height h. The duration (t0) of motion, when it reaches bottom of the tower is given by
A particle moves along the x-axis as x = u (t −2s) + a (t − 2s)2. The initial velocity of the particle is
u − 2a
u − 4a
2a − u
2a − 3u
Two masses m1 = 5 kg and m2 = 4.8 kg tied to a string are hanging over a light frictionless pulley. What is the acceleration of the masses when lift is free to move ?
0.2 m/s2
9.8 m/s2
5 m/s2
4.8 m/s2
A metal block of mass 1 kg is resting on a frictionless horizontal plane. It is struck by a jet releasing water at a rate of 1 m/s and at a speed of 4 m/s. Then, the initial acceleration of the block will be
2 m/s2
8 m/s2
1 m/s2
4 m/s2
A small ball released from rest from a height h on a smooth surface of varying inclination, as shown in figure.
The speed of the ball when it reaches the horizontal part of the surface is
None of these
A person travelling on a straight line moves with an uniform velocity v1 for some time and with uniform velocity v2 for the next equal interval of time. The average velocity for the entire duration is
( v1 + v2 )
(v1 + v2 ) / 2
(v1 + v2 ) / 3
(2v1 + 3v2 ) / 3
If the position of a moving particle, with respect to time be, x(t) = 1 + t − t2, then, the acceleration of particle is given by (assume all measurements in MKS)
− 1 ms-2
− 1.5 ms-2
− 2 ms-2
− 2.5 ms-2
A man wants to slide down a rope. The breaking load for the rope is rd ofthe weight of the man. With what minimum acceleration should fireman slide down?
g/4
g/3
2g/3
g/6
If a particle moves a distance x at a speed v1 and comes back with speed v2 , then the average speed and average velocity during this round trip will respectively be
0, v1 + v2
v1 + v2, 0
v1 − v2,
For the given position-time (x − t) graph , the interval in which velocity is zero, is
(t3 − t1)
(t3 − t2)
(t5 − t4)
(t5 − t2)
