Two objects of masses mi = 0.56 kg and m = 0.88 kg
are placed on a horizontal
frictionless surface and a
compressed spring of force
constant k = 280 N/m is
placed between them as
in Figure P6.28a. Neglect
the mass of the spring,
The spring is not attached
to either object and is
compressed a distance of
9.8 cm. If the objects are released from rest, find the final velocity of each object as shown in Figure P6.28b.

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?