Two parallel train tracks run from North to South. On one track train A is moving with a speed 30 m/s from North to South. An the other track a train B is moving with speed 50 m/s from South to North. The relative velocity of train A with respect to train B is

A. When a person jumps from the boat to the river, the boat goes backwards B. Passengers standing in a bus fall in the back direction, when the stationary bus suddenly moves C. When a person falls on the cement floor, he gets hurt D. While catching a fast moving cricket ball, a fielder puts his hands backwards

A. Isaac Newton B. Albert Einstein C. Niels Bohr D. Duncan Haldane

A. Explains the relationship between forces on two mutually effective objects B. Also known by the law of inertia C. It is helpful to understand the effects of force D. Also known by the law of conservation of energy

A. centrifugal force B. inertia C. centripetal force D. gravitational force