Question

In crash tests, a shock absorber is used to slow the test car. The shock absorber consists of a piston with small holes that moves in a cylinder containing water. Viscous dissipation in the water transforms work into heat. How much heat will be transferred from the water after a 2000 kg car crashes into the shock absorber at a speed of 40 m/s?

Answer 1

The heat transferred to water equals 1600 kJ

Step-by-step explanation:

By the conservation of energy we have

All the kinetic energy of the moving vehicle is converted into thermal energy

We know that kinetic energy of a object of mass 'm' moving with a speed of 'v' is given by

`K.E=(1)/(2)mv^(2)`

Thus

`K.E_(car)=(1)/(2)* 2000* 40^(2)=1600* 10^(3)Joules`

Thus the heat transferred to water equals
`1600kJ`