**Goal:** Developing strategic knowledge

**Source:** UMPERG-ctqpe85

A mass of 0.5 kg moving along a horizontal frictionless surface

encounters a spring having k = 200 N/m. The mass compresses the spring

by 0.1 meters before reversing its direction. Consider the total time

the mass is in contact with the spring. What is the total impulse

delivered to the mass by the spring?

Which of the following principles or combination of principles

could be used to solve this problem MOST EFFICIENTLY.

- Newton’s 2nd law & dynamics
- Work-Energy theorem
- Impulse-Momentum theorem
- 1 and 2
- 1 and 3
- 2 and 3
- Other

## Commentary:

## Answer

(6) This is a two-principle problem. Again, student response is

not as important as discussing what clues there are for deciding what

principles are needed.