Question

A body of mass 2 kg is moving with a velocity of 5 m/s. How much work is required to stop the body?

• A. 10 J
• B. 15 J
• C. 20 J
• D. 25 J

Hint:

Tip: Work done to stop a moving body is equal to its initial kinetic energy.

Answer 1

The Correct Option is D

Step 1: Use the work-energy principle. 
The work required to stop the body equals the loss in kinetic energy.

Step 2: Calculate initial kinetic energy. 
\[ KE = \frac{1}{2} m v^2 = \frac{1}{2} \cdot 2 \cdot (5)^2 = 25 \text{ J} \]

Step 3: Final velocity is 0, so all kinetic energy is lost. 
Hence, work done to stop the body = \( \boxed{25 \text{ J}} \)