Free JEE Main Physics Work by Constant Force MCQs with step-by-step solutions (2 questions). Part of Work, Power and Energy. Practise online on Prepizo — no login needed.
Q1 — Work by Constant Force · easy · numerical
A porter drags a 20 kg trunk 4 m across a platform with a 50 N force at 37° above the horizontal (cos37° = 0.8). The work done by the porter is:
A. 640 J
B. 200 J
C. 120 J
D. 160 J ✓ Correct
Solution: W = Fs cosθ = 50 × 4 × 0.8 = 160 J.
Q2 — Work by Constant Force · medium · numerical
A 10 kg suitcase is lifted from the floor onto a shelf 1.5 m high, then carried 10 m horizontally at the same height. The total work done against gravity is:
A. 150 J ✓ Correct
B. 1000 J
C. 1150 J
D. Zero
Solution: Against gravity: W = mgh = 10×10×1.5 = 150 J. The horizontal carry does no work against gravity (force ⊥ displacement) — the classic coolie trap.