The goal of this lab is to ride in an elevator and analyze the forces acting on you while you ride in the elevator. Some very counterintuitive forces act on you when riding the elevator! A counterintuitive force occurs when what you feel is not the same as the force actually acting on you.

Ride in an elevator. Begin on a high floor and ride down to a lower floor, then back up to a high floor. This experience works best in a high speed elevator, but works even in a low-speed elevator. As the elevator moves up and down, describe how you feel in six different situations.

Describe what you feel in each situation.

Break the situations into three categories.

• During two of the six situations, you feel like you are falling. Which two?
• During two of the six situations, you feel like the ground is pressing into you. Which two?
• During two of the six situations, you feel relatively normal. Which two?

The ultimate goal is to for each situation, draw a free-body diagram based on how you are moving, and then relate that to how you feel.

##### Rules for how you feel:
• If the normal force is weaker than your weight (gravity), you feel like you are falling.
• If the normal force is stronger than your weight (gravity), you feel like the ground is pressing into you.
• If the normal force is equal to your weight (gravity), you don't feel anything special.
##### Newton's First and Second Laws
• If the net force acting on you is in the same direction as your velocity, you speed up.
• If the net force acting on you is in the opposite direction as your velocity, you slow down.
• If the net force acting on you is zero, you move at a constant speed.

For each of the six situations above in the boxes, complete the following analysis:

• Describe how you feel in each situation, as though you are falling, being pressed into, or normal.
• Draw a qualitative free-body diagram. The free-body diagram should include only two forces in each case: gravity and normal force. Relate your free-body diagram to the way that you feel.
• Draw a qualitative net force vector. The net force vector should not be a part of your free-body diagram, but should be separate from it.
• Draw a qualitative velocity vector. The velocity vector should not be a part of your free-body diagram, but should be separate from it. The velocity vector always points in the direction that the elevator is moving.
• Using Newton's First and Second Laws, which are written above, determine whether you are speeding up, slowing down, or moving at a constant speed in each situation.

Write a one-paragraph final analysis. In the final analysis, describe your trip in the elevator, and relate how your motion (speeding up, slowing down, or moving at a constant speed), connects to your free-body diagram and Newton's First and Second Laws at each portion. Also identify which parts of the elevator write are the most counterintuitive? For most people, forces are counterinuitive when their net force and their velocity act in the opposite directions.