Concepts Of Physics MCQ Edition [Volume 2]PhysicsHeat and Temperature
A spinning wheel is brought into contact with an identical wheel spinning at an identical speed. The wheels slow down under the influence of friction. Which of the following energies of the first wheel decrease?
Options
- AMechanical
- BKinetic
- CInternal
- DTotal
Correct answer
B. Kinetic
Step-by-step solution
As the wheel slows down due to friction, its angular velocity decreases. Therefore, its kinetic energy decreases. Mechanical energy is the sum of kinetic and potential energy. Since the potential energy remains constant and the kinetic energy decreases, the mechanical energy also decreases. The work done by friction generates heat, which raises the temperature of the wheels. This causes an increase in the internal energy of the wheels. By symmetry, the heat generated is shared equally between the two identical whee