A 50 kg man climbs 30 steps each 20 cm high in 10 s. His power (g=10 m/s²) is MCQ with Answer and Explanation

A 50 kg man climbs 30 steps each 20 cm high in 10 s. His power (g=10 m/s²) is
A. 150 W
B. 30 W
C. 300 W
D. 600 W
Answer: Option C
Solution (By JKExamLibrary)
Total height = 30 × 0.2 m = 6 m. Work done = mgh = 50 × 10 × 6 = 3000 J. Power = Work/time = 3000/10 = 300 W. If steps height and number given, calculate total vertical displacement. Time taken for climbing is important. Power is rate of doing work.

This question belongs to: Science Physics

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Physics Questions

Question #1 Report Error
According to the Bohr model of the hydrogen atom, the total energy of an electron in the nth stationary orbit is directly proportional to:
A. 1 / n^2
B. n^2
C. 1 / n
D. n

Correct Answer: Option A


Explanation:
The total energy of an electron in a hydrogen-like atom in the nth orbit is strictly negative and given by the mathematical formula E_n = -13.6 Z^2 / n^2 (in eV). This formula demonstrates that the total energy is inversely proportional to the square of the principal quantum number (n^2).

This question belongs to: Science Physics
Question #2 Report Error
Simple harmonic motion is characterized by:
A. Acceleration proportional to velocity
B. Acceleration proportional to displacement and directed opposite
C. Constant velocity
D. Constant acceleration

Correct Answer: Option B


Explanation:
SHM definition: acceleration a ∝ -x (displacement), i.e., a = -ω²x. This restoring acceleration causes oscillatory motion. Constant acceleration implies uniformly accelerated motion (not oscillatory). Constant velocity implies no acceleration. Memory tip: 'SHM: a = -ω²x; force F = -kx (Hooke's law)'. This conceptual question tests fundamental SHM characteristics, frequently examined in competitive exams. Always link to examples: mass-spring system, simple pendulum (small angles), LC circuits.

This question belongs to: Science Physics
Question #3 Report Error
A body of mass 2 kg has momentum 10 kg·m/s. Its kinetic energy is:
A. 25 J
B. 100 J
C. 12.5 J
D. 50 J

Correct Answer: Option C


Explanation:
KE = p²/(2m) = (10)²/(2×2) = 100/4 = 25 J. Wait, recalculate: 100/4 = 25 J. Option B is correct. KE = p²/2m relates momentum and kinetic energy. Memory tip: When given momentum, use KE = p²/2m instead of finding velocity first. Efficient calculation method for competitive exam time constraints.

This question belongs to: Science Physics