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

Answer:

The heat transferred to water equals 1600 kJ

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

$K.E=\frac{1}{2}mv^{2}$

Thus

$K.E_{car}=\frac{1}{2}\times 2000\times 40^{2}=1600\times 10^{3}Joules$

Thus the heat transferred to water equals $1600kJ$