HELP! I have a Science test TOMORROW, and I need this filled out. Could you please help me?

Lets say that an object of a certain volume has a certin mass. what happens to its mass when you double its volume?

What causes the formation of ocean currents?

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.