91Ó°ÊÓ

Assume that there is no heat transfer occurring in this situation. The amount of heat transfer can be calculated using the expression;

\({\rm{Q = mc\Delta T}}\)

Here, \({\rm{Q}}\)is the amount of heat, \({\rm{m}}\)is the mass of the substance, \({\rm{c}}\)is the specific heat capacity, and\({\rm{\Delta T}}\)is the variation in temperature.

Here, the value \({\rm{Q}}\)is zero because there is no heat transfer. For this, \({\rm{\Delta T}}\)also have to be zero as well. That is, the temperature remains constant. In this situation, the speed decreased. In order to maintain the temperature at the rest position, breaks in the car increase the temperature.

The temperature is the measure of theaverage kinetic energy of atoms in a material. Kinetic energy is proportional to the square of velocity. So, the temperature will also be proportional to the square of the velocity. If the speed doubles, the temperature will become four times higher than the initial temperature.

So, \({\rm{\Delta T}}\) will be four times as large if the speed becomes twice the initial speed.