PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A crate rests on the flat bed of a truck. The truck’s motion is described in three consecutive time intervals.
• Interval A: The truck accelerates from rest to 10m/s in a straight line.
• Interval B: The truck travels straight at a steady 10m/s.
• Interval C: The driver applies the brakes and the truck slows to rest in a straight line.
Assume the crate does not slide relative to the truck. Which statement correctly identifies the interval(s) during which the horizontal net force on the crate is zero?
(a) Intervals A, B, and C
(b) Only Interval B
(c) Intervals A and B only
(d) Intervals B and C only