A machine gun fires 20 bullets per second into a target. Each bullet weighs 150 gms and has a speed of 800 m/sec. Find the force necessary to hold the gun in position
A man is standing at the centre of frictionless pond of ice. How can he get himself to the shore
A jet plane flies in the air because
A player caught a cricket ball of mass 150 gm moving at a rate of 20 m/s. If the catching process be completed in 0.1 s, then the force of the blow exerted by the ball on the hands of the player is
A rocket has a mass of 100 kg. 90% of this is fuel. It ejects fuel vapours at the rate of 1 kg/sec with a velocity of 500 m/sec relative to the rocket. It is supposed that the rocket is outside the gravitational field. The initial upthrust on the rocket when it just starts moving upwards is
In which of the following cases forces may not be required to keep the
A wagon weighing 1000 kg is moving with a velocity 50km/h on smooth horizontal rails. A mass of 250 kg is dropped into it. The velocity with which it moves now is
If a force of 250 N act on body, the momentum acquired is 125 kg-m/s. What is the period for which force acts on the body
A 100 g iron ball having velocity 10 m/s collides with a wall at an angle 30° and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the wall is
A ball of mass 150g starts moving with an acceleration of 20m/s² . When hit by a force, which acts on it for 0.1 sec. The impulsive force is
The motion of a rocket is based on the principle of conservation of
A rocket of mass 1000 kg exhausts gases at a rate of 4 kg/sec with a velocity 3000 m/s. The thrust developed on the rocket is
A bullet of mass 5 g is shot from a gun of mass 5 kg. The muzzle velocity of the bullet is 500 m/s. The recoil velocity of the gun is
A force of 50 dynes is acted on a body of mass 5 g which is at rest for an interval of 3 seconds, then impulse is
A body of mass M at rest explodes into three pieces, two of which of mass M/4 each are thrown off in perpendicular directions with velocities of 3 m/s and 4 m/s The third piece will be thrown off with a velocity of
A body of mass 0.25 kg is projected with muzzle velocity 100ms‾¹ from a tank of mass 100 kg. What is the recoil velocity of the tank
A bullet of mass 0.1 kg is fired with a speed of 100 m/sec, the mass of gun is 50 kg. The velocity of recoil is
A bullet mass 10 gm is fired from a gun of mass 1kg. If the recoil velocity is 5 m/s, the velocity of the muzzle is
At a certain instant of time the mass of a rocket going up vertically is 100 kg. If it is ejecting 5 kg of gas per second at a speed of 400 m/s, the acceleration of the rocket would be (taking g=10m/s²)
The weight of an aeroplane flying in the air is balanced by
Two forces of magnitude F have a resultant of the same magnitude F. The angle between the two forces is
An object is subjected to a force in the north-east direction. To balance this force, a second force should be applied in the direction
The resultant force of 5 N and 10 N can not be
The resultant of two forces 3P and2P is R. If the first force is doubled then the resultant is also doubled. The angle between the two forces is
The resultant of two forces, one double the other in magnitude, is perpendicular to the smaller of the two forces. The angle between the two forces is
