A student raises a 10 kg crate from the floor to a shelf 2 m high in three different ways
PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A student raises a 10 kg crate from the floor to a shelf 2 m high in three different ways, neglecting friction and air resistance.
• Path P: Directly upward at constant speed.
• Path Q: Slowly pushes the crate up a 4 m long friction-free ramp to the same shelf.
• Path R: Lifts the crate vertically while first speeding it up and then slowing it to rest on the shelf.
Rank the magnitude of the work WP, WQ, and WR done by the student.
(a) WQ>WR>WP
(b) WP=WQ=WR
(c) WR>WP>WQ
(d) WR=WP>WQ