A body of mass 2 kg has momentum 10 kg·m/s. Its kinetic energy is:
A. 12.5 J
B. 50 J
C. 100 J
D. 25 J
Answer: Option A
Solution (By JKSSB Mock Tests)
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.
Explanation:
In free fall under gravity alone, mechanical energy (kinetic + potential) is conserved, assuming no air resistance. Potential energy decreases while kinetic energy increases, sum constant. Law of conservation of mechanical energy. Non-conservative forces absent.
No comments yet. Be the first to start the discussion!