A man slides down a light rope whose breaking strength is η times his weight .What should be his maximum acceleration so that the rope does not break ?
g (1 - η)
ηg
g /1+η
g/1 - η
A body of mass 2 kg ,moving on a horizontal surface with an initial velocity of 4 m/s , comes to rest after 2 s.If one wants to keep this moving on the same surface with a velocity of 4 m/s,the force required is
2 N
4 N
6 N
10 N
A shell is fired from a canon, it explodes in mid air, its total
momentum increases
momentum decreases
kinetic energy increases
kinetic energy decreases
A block of metal of mass 2 kg is resting on a frictionless floor.It is struck by a jet releasing water at the rate of 1 kg/sec and at a speed of 5 m/s.What will be the initial acceleration of the block ?
3.5 m/s2
4.5 m/s2
2.5 m/s2
none of these
A cricket player catches a ball of mass 100 g and moving with a velocity of 25 ms-1. If the ball is caught in 0.1s, the force of the blow exerted on the hand of the player is
25 N
40 N
250 N
Two forces of 6N and 8N act on a body of mass 7kg. The maximum value of acceleration produced cannot be more than
2ms-1
4ms-1
6ms-1
8ms-1
A boy of mass 50 kg is standing on a weighing machine placed on the floor of a lift.The machine reads his weight in Newtons.What is the reading of the machine if the lift is moving upwards with a uniform speed of 10 m/sec2?
(g = 10 m/sec2 )
510 N
480 N
490 N
500 N
A gun of mass 1kg fires a bullet of mass 1g with a velcoity of 1ms-1.The recoil velcotiy of the gun is
1ms-1
0.1ms-1
0.01ms-1
0.001ms-1
A balloon contains 10 g of air. The air begins to escape from a small hole in the balloon at the rate of 4 cms-1 and it completely shrinks in 2 seconds. What is the average force on the balloon?
5 dyne
10 dyne
15 dyne
20 dyne
If the force on a rocket moving with a velocity of 300 m/s is 345 N, then the rate of combustion of the fuel ,is
0.55 kg/s
0.75 kg/s
1.15 kg/s
2.25 kg/s
