A2L Item 155
- Description: Identify the total impulse received by a mass reversing direction due to hitting and compressing a spring.
- Goal: Problem solving
- Source: UMPERG-ctqpe84
- Keywords: Energy, Impulse, Mechanics, Momentum, Problem Solving, Springs
The question for students:
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?
- -4 N-s
- -2 N-s
- 0 N-s
- 2 N-s
- 4 N-s
- none of the above
- cannot be determined.
Commentary for teachers:
Answer
(2) This problem requires students to put together the concepts of kinetic and potential energy, and change of momentum. Some may be tempted to resort to the definition of impulse and try to determine the force due to the spring.