What should a free-body diagram look like for a skydiver that is still speeding up as he falls? there is an arrow up for air resistance and an arrow down for gravity. the arrows are the same length. there is an arrow up for air resistance and an arrow down for gravity. the arrow up is longer than the arrow down. there is an arrow up for air resistance and an arrow down for gravity. the arrow up is shorter than the arrow down. there is only an arrow down for gravity

There is an arrow up for the air resistance and an arrow down for gravity. The arrow up is shorter than the arrow down.

Explanation:

So in the free-body diagram you have to draw all the forces that are acting over some body.

In this case when the skydiver is falling down there are only 2 forces acting on him, the gravitational force and the air resistance, therefore in the free-body diagram should be 2 arrows, now we have to determinate the direction of this arrows, so like the gravitational force is pulling the skydiver down (towards to earth) the arrow for this one should be down, and for the air resistance as it's trying to stop skydiver's fall it's direction it's upwards. now for the length of the arrows we have to look in which direction is the skydiver speeding up, in the question it says that the skydiver is speeding up down so the bigger arrow should be downwards too.

this means that the temperature of both substances will be equal