A person at rest is observing two trains one coming towards him and other leaving with the same speed 4 m/s. If their whistling frequencies are 240 Hz each, then the number of beats per second heard by the person will be (if velocity of sound is 320 m/s)

If the spinning speed of earth is increased then the weight of the body at equator

The weight of a body on the earth is 400 N. Then weight of the body when taken to a depth half of the radius of the earth will be

A body weighs 200 N on the surface of the earth. How much will it weigh half way down to the centre of the earth?

Two particles of masses 4kg and 8kg are kept at x = - 2m and x = 4m respectively. Then, the gravitational field intensity at the origin is

Statement A : Shock absorbers reduce the magnitude of change in momentum.

Statement B : Shock absorbers increase the time of action of impulsive force