Two frictionless tracks carry identical carts of mass from point A (at height above…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Two frictionless tracks carry identical carts of mass m from point A (at height H above reference level) to point B (at the reference level).
• Track 1 drops steeply for a short horizontal distance and then becomes level well before reaching B.
• Track 2 descends along a gentle, constant incline all the way to B.
Assume both carts start from rest at A and that friction and air resistance are negligible.
(1) Part 1: (a) Rank the carts’ speeds as they pass point B from greatest to least, indicating any ties. Provide a qualitative justification based on energy considerations.
(2) Part 2: (b) Rank the elapsed travel times from A to B for the two carts and justify your answer conceptually, making explicit reference to the shape of each track.
(3) Part 3: (c) A student claims that because both carts lose the same amount of gravitational potential energy, their accelerations must have been identical at every point along the tracks. Evaluate the validity of this claim and support your reasoning qualitatively.