alleryA body of mass 5 kg is raised vertically by 4 m at constant velocity (g = 10 m s⁻²). The work done against gravity is:
A100 J
B150 J
C200 J
D250 J
Answer & Solution
Correct answer: C. 200 J
1. Force needed to lift at constant velocity equals weight: F = m g = 5 × 10 = 50 N.
2. Displacement is 4 m, parallel to force.
3. W = F · d = 50 × 4 = 200 J.
_Source: syllabus Physics Ch 5, §5.2 (worked-example methodology), p. 77_
Keep practising Work, Energy and Power
Browse all Work, Energy and Power questions for AP Intermediate 1st Year, or explore more Physics topics.
Related questions
A particle moves under a force F = −k x. The motion is:In a perfectly inelastic collision between two bodies:A spring with spring constant k is compressed by x. The elastic potential energy stored isIn a one-dimensional elastic collision between a moving body and an equal-mass stationary Two bodies of masses m₁ and m₂ have equal kinetic energies. The ratio of their momenta p₁/A pump lifts water at a rate of 3000 kg per minute through 30 m (g = 10 m s⁻²). The minimuA 60 W bulb burns for 2 hours. The total energy consumed in kWh is:A body is dropped from height h. Just before it hits the ground, its speed is: