A body of mass 4 kg weighs 4.8 kg when suspended in a moving lift. The acceleration of the lift is
An elevator weighing 6000 kg is pulled upward by a cable with an acceleration of 5 ms‾² . Taking g to be 10 ms‾² , then the tension in the cable is
A ball of mass 0.2 kg moves with a velocity of 20 m/sec and it stops in 0.1 sec; then the force on the ball is
A vehicle of 100 kg is moving with a velocity of 5 m/sec. To stop it in 1/10, the required force in opposite direction is
A boy having a mass equal to 40 kilograms is standing in an elevator. The force felt by the feet of the boy will be greatest when the elevator (g=9.8 meters/sec²)
The ratio of the weight of a man in a stationary lift and when it is moving downward with uniform acceleration ‘a’ is 3 : 2. The value of ‘a’ is (g-Acceleration due to gravity of the earth)
The mass of a lift is 500 kg. When it ascends with an acceleration of 2 m/s², the tension in the cable will be (g=10 m/s²)
If force on a rocket having exhaust velocity of 300 m/sec is 210 N, then rate of combustion of the fuel is
In an elevator moving vertically up with an acceleration g, the force exerted on the floor by a passenger of mass M is
A mass 1 kg is suspended by a thread. It is
(i) lifted up with an acceleration 4.9 m/s²
(ii) lowered with an acceleration 4.9 m/s²
The ratio of the tensions is
A 5000 kg rocket is set for vertical firing. The exhaust speed is 800 ms‾¹ . To give an initial upward acceleration of 20 ms‾² , the amount of gas ejected per second to supply the needed thrust will be (g=10 ms‾²)
If a person with a spring balance and a body hanging from it goes up and up in an aeroplane, then the reading of the weight of the body as indicated by the spring balance will
The time period of a simple pendulum measured inside a stationary lift is found to be T. If the lift starts accelerating upwards with an acceleration g/3, the time period is
A cork is submerged in water by a spring attached to the bottom of a pail. When the pail is kept in a elevator moving with an acceleration downwards, the spring length
A boy of 50 kg is in a lift moving down with an acceleration 9.8 ms‾². The apparent weight of the body is (g=9.8 ms‾²)
A body is imparted motion from rest to move in a straight line. If it is then obstructed by an opposite force, then
A mass of 10 gm is suspended by a string and the entire system is falling with a uniform acceleration of 400 cm/sec² The tension in the string will be (980 cm/s²)
A second's pendulum is mounted in a rocket. Its period of oscillation decreases when the rocket
A cart of mass M is tied by one end of a massless rope of length 10 m. The other end of the rope is in the hands of a man of mass M. The entire system is on a smooth horizontal surface. The man is at x = 0 and the cart at x = 10 m. If the man pulls the cart by the rope, the man and the cart will meet at the point
A cricket ball of mass 250 g collides with a bat with velocity 10 m/s and returns with the same velocity within 0.01 second. The force acted on bat is
A pendulum bob of mass 50 gm is suspended from the ceiling of an elevator. The tension in the string if the elevator goes up with uniform velocity is approximately
A train is moving with velocity 20 m/sec. on this dust is falling at the rate of 50 kg/minute. The extra force required to move this train with constant velocity will be
The average force necessary to stop a bullet of mass 20 g moving with a speed of 250 m/s, as it penetrates into the wood for a distance of 12 cm is
The average resisting force that must act on a 5 kg mass to reduce its speed from 65 cm/s to 15 cm/s in 0.2s is
An army vehicle of mass 1000 kg is moving with a velocity of 10 m/s and is acted upon by a forward force of 1000 N due to the engine and a retarding force of 500 N due to friction. What will be its velocity after 10 s
