A man of weight 80 kg is standing in an elevator which is moving with an acceleration of 6m/s² in upward direction. The apparent weight of the man will be (g=10m/s²)
A force of 100 dynes acts on a mass of 5 gram for 10 sec. The velocity produced is
When the speed of a moving body is doubled
A body of mass m collides against a wall with a velocity v and rebounds with the same speed. Its change of momentum is
A thief stole a box full of valuable articles of weight W and while carrying it on his back, he jumped down a wall of height ‘h’ from the ground. Before he reached the ground he experienced a load of
N bullets each of mass m kg are fired with a velocity at the rate of n bullets per second upon a wall. The reaction offered by the wall to the bullets is given by
If a body of mass m is carried by a lift moving with an upward acceleration a, then the forces acting on the body are (i) the reaction R on the floor of the lift upwards (ii) the weight mg of the body acting vertically downwards. The equation of motion will be given by
With what minimum acceleration can a fireman slides down a rope while breaking strength of the rope is 2/3 of his weight
A ball of mass m moves with speed v and it strikes normally with a wall and reflected back normally, if its time of contact with wall is t then find force exerted by ball on wall
The velocity of a body at time t = 0 is m/s in the north-east direction and it is moving with an acceleration of 2 m/s2 directed towards the south. The magnitude and direction of the velocity of the body after 5 sec will be
A body of mass 8kg is moved by a force F=3x N, where x is the distance covered. Initial position is x=2m and the final position is x=10 m. The initial speed is 0.0m/s The final speed is
A ball of mass 0.5 kg moving with a velocity of 2 m/sec strikes a wall normally and bounces back with the same speed. If the time of contact between the ball and the wall is one millisecond, the average force exerted by the wall on the ball is
n small balls each of mass m impinge elastically each second on a surface with velocity u. The force experienced by the surface will be
A ball of mass 400 gm is dropped from a height of 5m. A boy on the ground hits the ball vertically upwards with a bat with an average force of 100 newton so that it attains a vertical height of 20 m. The time for which the ball remains in contact with the bat is [g=10m/s²]
The time in which a force of 2 N produces a change of momentum of 0.4kg-ms‾¹ in the body is
A gun of mass 10kg fires 4 bullets per second. The mass of each bullet is 20 g and the velocity of the bullet when it leaves the gun is 300ms‾¹ The force required to hold the gun while firing is
A gardner waters the plants by a pipe of diameter 1mm. The water comes out at the rate or 10 cm3/sec. The reactionary force exerted on the hand of the gardner is
A solid disc of mass M is just held in air horizontally by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 ms‾¹ . If the mass of each stone is 0.05kg what is the mass of the disc(g=10ms‾²)
A man is at rest in the middle of a pond on perfectly smooth ice. He can get himself to the shore by making use of Newton's
A cannon after firing recoils due to
A man is carrying a block of a certain substance (of density 1000kgm‾³ ) weighing 1 kg in his left hand and a bucket filled with water and weighing 10 kg in his right hand. He drops the block into the bucket. How much load does he carry in his right hand now
A man is standing on a balance and his weight is measured. If he takes a step in the left side, then weight
A man is standing at a spring platform. Reading of spring balance is 60 kg wt. If man jumps outside platform, then reading of spring balance
A bird is sitting in a large closed cage which is placed on a spring balance. It records a weight of 25 N. The bird (mass m = 0.5 kg) flies upward in the cage with an acceleration of 2m/s² . The spring balance will now record a weight of
A light spring balance hangs from the hook of the other light spring balance and a block of mass M kg hangs from the former one. Then the true statement about the scale reading is
