5.A student finds a spring that is labeled k=45 N/m. She hangs it vertically and attaches a 500 g mass to
it. If the spring is originally 30 cm long, how long will it stretch when the mass is attached?

Apair of 10μf capacitors in a high-power laser are charged to 1.7 kv. a. what charge is stored in each capacitor? b. how much energy is stored in each capacitor?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

Which best describes the difference between internal and thermal energy?