Explain why the books will not slide down the ramps at the same speed.

a. the sandpaper ramp will have more friction than the wood ramp.

b. the book on the wood ramp has more gravity pulling on it.

c. the wood ramp will have more friction then the sandpaper ramp.

d. the sandpaper ramp is higher than the wood ramp.

explain why you choose the answer you did.

A.The sandpaper ramp will have more friction than the wood ramp.

A. is the correct answer. The granules on the sandpaper cause friction which will cause the book to slow down because there is more resistance.

It maybe because uranus is made of gas but uranus has a solid core in the middle

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.