Asled sliding on a flat, icy surface with a constant velocity is best described by a)newtons first law of motion because the sled is moving at a constant velocity b)newtons second law of motion because the sled has less mass then the ice c)newtons law of gravity because gravity is pulling the sled down a hill d) newtons third law of motion because the sled will eventually come to a stop i feel this one is d but explain why u choose the awnser nate drops a penny into a fountain at the mall. it falls from his hand straight down into the foutain. describe what the free body diagram would look like as the penny falls. choose all that are true the arrow pointing down will be longer then the arrow pointing up the arrow pointing up would be longer then the arrow pointing down the arrow pointing to the left would be the same size as the one pointing to the right the arrow pointing to the left would be longer then the one pointing to the right i feel this one is the first and 3rd one but explain why u choose the awnser

The first one is actually Newton's First Law of Motion. 

Newton's First Law of Motion is commonly stated as "an object in motion will remain in motion unless acted upon by an outside force." This sled is moving across the ice at the same constant speed and velocity meaning it will won't stop unless an outside force acts upon it. An example being someone coming and grabbing the sled or maybe the sled slips off of the ice and finds itself stuck in a pile of snow. Similarly, if the sled was not moving, it would not move unless acted upon again by an outside force. 

You believed it to be Newton's Third Law, but for future reference, his third law is more about every action having an equal opposite reaction. This wouldn't explain what is currently happening with the sled. A helpful tip into figuring out where to start in figuring out the answer I got is in the example you gave it literally states "with a constant velocity" which also ends up being in the description of Newton's First Law. Though, don't rely on that because the answer could have had a made up definition.

Unfortunately, I do not know the answer to your other question. I apologize. Hope this helped.

Then the answer would be d then