Answer:
READ THIS FIRST!!!
I am not going to right the parragraph (it says to use your own words, they could trace it back to me if you use my words, and you would get it trouble).
But I will tell you the forces acting on the pencil:
Gravity (pulls on the pencil)
Your hand (pushing it up canceling out gravity)
And the electromagnetic force (holding the thing together)
Hope it helped,
Have a good day
Answer:
The answer is
. Let's learn why.
Explanation:
Newton's law of universal gravitation says;

Here G is a universal gravitational <u>constant</u> and is measured experimentally.
Sun's gravitational pull on mercury is:

Therefore 
Sun's gravitational pull on Earth is:

Therefore 
As a result;

(a) For the work-energy theorem, the work done to lift the can of paint is equal to the gravitational potential energy gained by it, therefore it is equal to

where m=3.4 kg is the mass of the can, g=9.81 m/s^2 is the gravitational acceleration and
is the variation of height. Substituting the numbers into the formula, we find

(b) In this case, the work done is zero. In fact, we know from its definition that the work done on an object is equal to the product between the force applied F and the displacement:

However, in this case there is no displacement, so d=0 and W=0, therefore the work done to hold the can stationary is zero.
(c) In this case, the work done is negative, because the work to lower the can back to the ground is done by the force of gravity, which pushes downward. Its value is given by the same formula used in part (a):
