Please Help A 6.0 kg cart moves at a velocity of 12 m/s. The cart bounces off a wall causing it to rebound in the opposite direction at a speed of 18 m/s.

What is the change in the earth's momentum? At for collision is 0.45 earths is the average force from the wall on the cart?
Delta t for collisions is 0.4s

Arock is dropped from a cliff and reaches the ground in 2.70s. at the same time another rock is thrown horizontally from the same height with initial x velocity of 0.95 m/s. what distance will in x will the second rock cover?

Which best represents the law of conservation of mass ?

Because air contracts as it cools, the air pressure inside a freezer is typically lower than on the outside. why do ice cubes inside a freezer tend to shrink over time? a. the ice dissolves oxygen from the air, forming a denser crystalline matrix. b. the ice reacts chemically with carbon dioxide in the air, forming gaseous carbon compounds. c. the ice melts, and then the liquid freezes as ice crystals on the bottom of the freezer. d. the ice sublimes, and then the water vapor deposits as ice crystals on the sides of the freezer.