A2L Item 145

Goal: Reasoning with energy

Source: UMPERG-ctqpe64

Two
masses, M > m, travel down the surfaces shown. Both surfaces are
frictionless. Which mass has the largest speed at the bottom?

  1. m
  2. M
  3. Both have the same speed
  4. Cannot be determined

Commentary:

Answer

(3) By energy considerations, both would have the same speed.
Students frequently get confused about the mass, thinking that the
larger mass has the greatest potential energy change and therefore has
the greatest speed.