Question

When an object falls freely towards the earth, then its total energy:

• A. Increases
• B. Decreases
• C. Remains constant
• D. First increases and then decreases

Hint:

In real-world conditions, air resistance causes some energy to be converted into heat, which is why total mechanical energy slightly decreases over time.

Answer 1

The Correct Option is C

Concept: The principle of the Conservation of Energy states that in an isolated system, energy is neither created nor destroyed. During free fall, energy is only transformed between potential and kinetic states.

Step 1: Analyzing potential energy.
As an object falls from a height, its height ($h$) above the ground decreases, leading to a decrease in its potential energy ($PE = mgh$).

Step 2: Analyzing kinetic energy.
As the object falls, it gains speed under the influence of gravity, leading to an increase in its kinetic energy ($KE = \frac{1}{2}mv^2$).

Step 3: Relating the two.
In a vacuum or under ideal conditions where air resistance is negligible, the amount of potential energy lost is exactly compensated by the amount of kinetic energy gained, keeping the total mechanical energy sum unchanged. equation Total Energy = Potential Energy + Kinetic Energy = Constant equation center Remains constant center