Question

Two spherical balls of the same radius, but of different masses, are dropped at the same time from the top of a tower $19.6\mathrm{m}$ high. When they are $1.6\mathrm{m}$ above the ground, the balls will possess the same

• A. K.E.
• B. P.E.
• C. momentum
• D. total energy

Answer 1

The correct option is D

total energy

The explanation for the correct option:

The correct option is D. total energy

1. For a body in motion, falling from a height, the potential energy decreases with height, and kinetic energy increases.
2. The total energy, which is the sum of potential and kinetic energy, remains constant at any instant of the motion.
3. For the two spheres of different masses, when dropped from the same height, the balls possess the same total energy at $1.6\mathrm{m}$ above the ground.

The explanation for the incorrect options:

A. K.E.

The kinetic energy of a body depends on its mass. As the two bodies differ in mass, their kinetic energy will be different at any instant of motion.

B. P.E.

The potential energy of a body depends on its mass. As the two bodies differ in mass, their potential energy will be different at any instant of motion.

C. momentum

The momentum of a body depends on its mass. As the two bodies differ in mass, their momentum will be different at any instant of motion.

Hence the correct answer is D.