Do you mind asking this question in another way
Answer:
Zero because the applied force is perpendicular to the motion of the object.
No work is done on an object moving is a circular path about a central attractive force.
Any work done in such a case would result in a change in the orbit.
No. If I count the number of tiny blue eggs in a Robin's nest, that's a quantitative observation.
Answer:
Its mechanical energy is the same.
Explanation:
If forces are only conservative, the mechanical energy will be the same.
It can be different if energy get transformed in another kind of energy like elastic energy for example, although the amount of energy is always the same.
If we just have mechanical energy not geting transformed we have:
Em=K+U
Em: Mechanical energy
K: Kinetic energý
U: Potential energy
Then if Kinetic energy decreases 10J, Potential energy will grow up 10J to keep the same amount of mechanical energy.