Answer:
F=248.5W N
Explanation:
Newton's 2nd Law tells us that F=ma. We will use their averages always. The average acceleration the tennis ball experimented is, by definition:

Since we start counting at 0s and the ball departs from rest, this is just 
So we can write:

Where in the last step we have just multiplied and divided by g, the acceleration of gravity. This allows us to introduce the weight of the ball W since W=gm, so we have:

Substituting our values:

Where the average force exerted has been written it terms of the tennis ball's weight W.
Answer: heat
Insulation Traps Heat. Keeping the cold air out
Explanation:
Answer:
The answer is diagram B I tried it out and it worked
Explanation:
B. A book sitting on a shelf. The books force is going down while the shelf's force is moving up against the book at an equal force.The answer would be B.