Question

What is the cause of heat generation in the following situations: a) we apply brakes on our fast moving car b) people often jump up and down to feel warmer in cold weather

Answer 1

When we apply brakes on fast moving car, the friction is created between the tyres and road this heavy friction wears out the tyre and generate heat.
While during jumping our blood flow gets fast, hearts getting beating up fast and this cause generation of heat.

Answer 2

Answer:

( a )  we apply brakes on our fast moving car

On applying the brakes of care, the kinetic energy of tyre gets converted to heat energy due to the friction between brakes and the tyre surface.

Therefore,

the Friction between the brakes and road causes heat generation.

(b) people often jump up and down to feel warmer in cold weather

When we are jumping up and down, our heart beat and blood flow increases therefore which make us feel warmer

Therefore,

The increased blood flow causes heat generation.