Question

Answer the question:
A cyclist travels down a hill from rest at point X, without pedalling.
The cyclist applies his brakes and thw cycle stops at point Y.
Which energy changes have taken place between X and Y ?

• A. gravitational potential $\to$ kinetic $\to$ thermal (heat)
• B. gravitational potential $\to$ thermal (heat) $\to$ kinetic
• C. kinetic $\to$ gravitational potential $\to$ thermal (heat)
• D. kinetic $\to$ thermal (heat) $\to$ gravitational potential

Answer 1

The correct option is A gravitational potential $\to$ kinetic $\to$ thermal (heat)

When cyclist is at point X , he has gravitational potential energy due to it's height.

Between X to Y , this energy gets converted to kinetic energy and cyclist get speed.

till point Y he applies break and convert that kinetic energy to heat or thermal energy.

Hence the correct order is

gravitational potential → kinetic → thermal (heat)

Hence option A is correct.