The piece of exercise equipment shown below includes two handles that are on each end of two parallel springs, each with a stiffness 500 N/m. To build strength, a person holds the two handles and pulls them apart with equal magnitude forces applied in opposite directions to the handles, thus stretching the springs. Neglect the mass of the springs and assume that they are pulled horizontally.
Two parallel springs between two handles that can be pulled apart.
- How much work must a person do to stretch the springs 5 cm?
- Suppose that a person is already holding the handles so that the springs are stretched 5 cm from their relaxed lengths. How much more work must the person do to stretch the springs an additional 5 cm (i.e. from 5 cm stretched to 10 cm stretched)?