Law of Conservation of Mechanical Energy — JEE Main Physics MCQs with Solutions
Free JEE Main Physics Law of Conservation of Mechanical Energy MCQs with step-by-step solutions (2 questions). Part of Work, Power and Energy. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Law of Conservation of Mechanical Energy · easy · numerical
A ball is thrown vertically downward at 10 m/s from a height of 15 m. Its speed on hitting the ground is:
A. 15 m/s
B. 25 m/s
C. 20 m/s ✓ Correct
D. 17.3 m/s
Solution: v² = u² + 2gh = 100 + 300 = 400 ⇒ v = 20 m/s (energy method: ½mv² = ½mu² + mgh).
Q2 — Law of Conservation of Mechanical Energy · medium · numerical
A ball thrown vertically up at 20 m/s has a speed of 10 m/s at height h. Then h equals:
A. 10 m
B. 15 m ✓ Correct
C. 5 m
D. 20 m
Solution: mgh = ½m(u² − v²) ⇒ h = (400 − 100)/(2×10) = 15 m.