**Goal:** Problem solving and developing strategic knowledge

**Source:** UMPERG-ctqpe100

You are given this problem:

A

mass m slides down a frictionless track of radius R=0.5m. Relative to

the center of curvature, what is the angular acceleration of the mass as

it reaches the bottom of the track.

What principle would you use to solve the problem MOST

EFFICIENTLY.

- Kinematics only
- F = ma or Newton’s laws
- Work-Energy theorem
- Impulse-Momentum theorem
- Angular Impulse-Angular Momentum
- 1 & 2
- 1 & 3
- 2 & 3
- none of the above
- not enough information given

## Commentary:

## Answer

(7) Students often think this problem requires angular momentum

or angular dynamics. Many cue on anything circular. Some students may

answer #10 thinking that the mass is needed.