A baseball would hit the bat harder. This is because the baseball is a lot heavier and more dense than the plastic ball. The keyword that you're looking for is density. The baseball is dense.
The answer would be, "1/560 seconds".
Answer:
If you increase either mass or velocity, the momentum of the object increases proportionally.
Answer:
1.40 N
Explanation:
The magnitude of the frictional force is given by:
where
is the coefficient of friction
N is the magnitude of the normal reaction
The coefficient of friction for this problem is 
. The magnitude of the normal reaction is equal to the combined weight of the boy and the sled, because the surface is horizontal, so
Therefore, the frictional force is
