Work Energy and...

Which one of the following energies cannot be possessed by a body at rest?

A ball of mass $$m$$ is attached with the string of length $$R$$, rotating in circular motion, with instantaneous velocity $$v$$ and centripetal acceleration $$a$$.

A car standing at the top of a hill would be an example of what type of energy?

A stone ties to a rope is rotated in a vertical circle with uniform speed. If the difference between the maximum and minimum tension in the rope is $$20\  N$$, mass of the stone in $$kg$$ is:
 ($$\displaystyle g=10{ ms }^{ -2 }$$)

In vertical circular motion, the ratio of kinetic energy to potential energy at the horizontal position is ____________.

An object of mass $$40\ kg$$ is raised to a height of $$5\ m$$ above ground. If the object is allowed to fall down find its kinetic energy when it is half-way down.

If the string were to break at point II, what would be the path of the ball?

A $$50 kg$$ acrobat is swinging on a rope with a length of $$15 m$$ from one horizontal platform to another. Both platforms are at equal height.
If the maximum tension the rope can support is $$1200 N$$, which of the following answer best represents the maximum velocity the acrobat can reach without breaking the rope?

Which of the following statements is true?

Fifteen joules of work is done on object A, which is attached to an uncompressed spring, so that all the work done goes into compressing the spring.
Sixty joules of work is done on object B, which is attached to an uncompressed spring that is identical to the spring to which object A is attached; all the work done goes into compressing the spring.
How does the compression of the spring for object B compare to the compression of the spring for object A after this work is done?