(a)In 'high jump' event the athletes are made to fall on a cushioned bed. Why?
(b)What is the use of seat belts in cars?

Explain the use of seat belts of cars.

Seat belts in cars are called safety belts. Why?

A cushioned bed or a sand bed is used in the athletic event high jump. Why?

A ball falls to the ground as shown below : (a) What is the kinetic energy of ball when it hits the ground ? (b) What is the potential energy of ball at B ? (c) Which law you have made use of in answering this question ?

(a) In the formation of compound between two atoms A and B, A loses two electrons and B gains one electron. (i) What is the nature of bond between A and B? (ii) Suggest the formula of the compound formed between A and B. (b) On similar lines explain the formation of MgCl_(2) molecule. (c ) Common salt conducts electricity only in the molten state. Why? (d) Why is melting point of NaCl high ?

A person driving a car suddenly applies the brakes on seeing a child on the road ahead . If he is not wearing seat belt, he falls forward and hits his head against the steering weel. Why ?

(a) If ratio are made to fall of two bodies is 1: 2, what is the ratio of their heights of fall ? (b) Two bodies are made to fall from two different height in the ratio 9:4 . What will be the ratio of their times of fall ?