If 1) we could make a truly frictionless surface, and I hit a hockey puck along this surface, will it ever stop? Why or why not? If it was possible to make a frictionless surface then the hockey puck would continue to move until it was acted up on by an outside force. This is explained by Newton's laws stating that an object in motion stays in motion unless acted up by an outside force. 2) Two people pull on a box with ropes in opposite directions. One pulls with a force of 10N to the left, the other pulls with a force of 5N to the right. What is the net force on the box? Briefly explain your reasoning. The net force is -5N because the two forces work together in a sense to achieve an equilibrium. Once that equilibrium is surpassed then the greater force causes the box to move either in a or positive negative direction. In this case the box moves with a force of 5N to the left or -5N 3) If I have a 600kg asteroid in space, and I accelerate it with an acceleration of `$10m/s^2$`, what is the force I have to use to achieve this? Briefly indicate how you arrived at your answer. F=M x A So 600 x 10m/S = the force necessary to move the asteroid. So the force necessary is 6000N 4) You stand on the sidewalk on campus. You are pulled down by the force due to gravity. Why don't you sink through the sidewalk? The reason you don't sink through the side walk is due to the fact that the earth is pushing back up on you at an equal rate which is an affect due to you pushing down. There is an equal force pushing on you upwards and down wards and you are pushing back upwards and downwards.