This question is typical on some driver license exams: a car moving at 43 km/h skids 17 m with locked brakes. how far will the car skid with locked brakes at 129 km/h? assume that energy loss is due only to sliding friction.
answer in units of m.

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?