A student investigates how the acceleration of a wooden cart changes when additional…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A student investigates how the acceleration of a wooden cart changes when additional objects are placed on the cart while the same horizontal pulling force is applied with a spring scale. In the first trial the empty cart accelerates at 0.60m⋅s−2. In the second trial the student firmly attaches an identical second cart on top of the first so that the two move together as one system; the applied horizontal force is unchanged.
Assume friction and air resistance are negligible.
(1) Describe qualitatively how the acceleration of the two–cart system in the second trial compares to that of the single-cart system in the first trial. In your description, refer explicitly to how the net external force and the total mass of the system affect the acceleration.
(2) If the acceleration measured in the second trial is 0.30m⋅s−2, determine what this result implies about the mass of the second cart relative to the mass of the first. Show your reasoning in words or symbols.
(3) Suppose the carts are not identical after all, and the second cart is actually more massive than the first. Explain how the student could use only the measured accelerations (no direct mass measurements) to calculate the exact mass of the second cart. Outline the required steps without performing numerical calculations.