A paper placed in between two books can be quickly pulled out without moving the books. Which statement explains this phenomenon? A.
There are no forces acting between the books and the paper.
B.
The pull of gravity on the book is greater than the force of gravity on the paper.
C.
The two books exert force only on each other and not on the paper.
D.
The books have a great deal of inertia and do not move easily.

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?