Question

Which of the following energy transformations take place when a skydiver jumps from an airplane with a parachute?
A. Solar – Kinetic
B. Kinetic – Wind
C. Potential – Kinetic
D. None of these

Answer 1

Hint: When a body is present at a certain height and is at rest, it possesses energy known as potential energy. When there is movement shown by a body, it is said to possess kinetic energy. When a skydiver dives from an airplane, He/she from a certain height reaches the ground with a certain velocity. Thus, the conversion is from potential energy to kinetic energy.

Complete Answer: When a body is present at a certain height and is at rest, it possesses energy known as the potential energy. The potential energy is given by mgh, where m is the mass of the body, g is the acceleration due to gravity, and his the body’s height from the earth’s surface.
When there is movement shown by a body, it is said to possess kinetic energy given by $\dfrac{1}{2}m{v^2}$, where m is the mass of the body and v is its velocity.
When a skydiver dives from an airplane, He/she from a certain height reaches the ground with a certain velocity. Thus, the conversion is as follows: Potential energy to Kinetic energy
Therefore, option C is correct.
Additional Information: : We can prove the formula for kinetic energy by Newton's 3rd law of motion.
We know that ${v^2} - {u^2} = 2as$ (v is final velocity, u is initial velocity, a is acceleration and s is the displacement. Multiplying half and m to both sides.
$\dfrac{1}{2}m{v^2} - \dfrac{1}{2}m{u^2} = mas$ (ma=f) (F is force) and $Fxs = W$ which is the work done.
Therefore, the final K.E subtracted by the initial K.E is the work done by the body.

Note: One can clearly see that options A and B are totally absurd as a human cannot possess solar energy and neither wind energy. Therefore, one can attempt this question with the elimination of options if not knowing the theoretical part.