Energy conservation with friction

Steps:

• Loss in gravitational potential energy: $mgh = 500 \times 10 \times 30 = 1.5 \times 10^5$ J.
• Gain in kinetic energy: $\frac{1}{2}mv^2 = \frac{1}{2} \times 500 \times 11^2 = 3.025 \times 10^4$ J.
• Energy dissipated by friction: potential energy loss minus kinetic energy gain = $1.5 \times 10^5 - 3.025 \times 10^4 \approx 1 \times 10^5$ J.
• This matches option B.

Why B is correct:

• It equals the difference between initial potential energy and final kinetic energy, per the work-energy principle.

Why the others are wrong:

• A is the kinetic energy gained.
• C is the total potential energy lost.
• D is an incorrect partial subtraction.

Final answer: B