Question

Consider an object falling from a terrace of height 20m above ground level. At what point does it posses maximum kinetic energy?

• A. 20m height
• B. 10m height
• C. When object touched the ground floor
• D. Just before touching the ground floor

Answer 1

The correct option is D

Just before touching the ground floor

According to the law of conservation of energy, the object which is falling freely from the terrace will have maximum potential energy at a height of 20m. Since the velocity of the object increases when it falls, its kinetic energy which is equal to $\frac{1}{2}m{v}^2$ will be maximum just before touching the ground. Also, it can be noted that the initial potential energy is equal to final kinetic energy by neglecting air losses.