Please help me with these two questions...I kinda know where to start, but If I jsut saw it worked out once I could do all of them of this style, so please help. Question 1: "A 65-kg paratrooper is falling, and hits the ground at 4 m/s. He makes an indentation 0.2 m deep in the ground. What force does he hit the ground with?" Question 2: This one is complicated: A 4000 kg train car is atop a 5 degree incline which is 5 m high (from baseline to top of hill, making it about 57 m long). It begins rolling down. The coefficient of the rolling frciton is 0.05 which is also static friction. At the bottom of the incline, it attaches to 3 identical carts. What is the final velocity of all 4 carts (when they form a train)?