Work - Energy theorem : Stopping distance

Formal write up.

Purpose:

• To confirm the relationship between the energy and work by exploring the amount of work necessary to remove the energy from the object.
• Display an understanding of internal and external forces and how they affect the energy of a system by describing their application to the physical system.

Background:

f_g = is weight = m*g , this is equal to the normal force

Example with height at 2.0 [m]

PE_top= mgh

Materials:

• Elevated track
• steel bearing(s)
• meter stick
• Logger pro, etc. with force meter
• 1/2 cardboard box

Part A: Determine the coefficient of friction, μ , between the cardboard box and the surface it is on.

1. By placing different masses into the 1/2 cardboard box and pulling at a constant velocity, you will determine the coefficient of kinetic (sliding) friction for the two surfaces.
2. Data Table for finding coefficient of sliding friction. You will use the coefficient of sliding friction for calculating the Friction that stops the barring in the box.

3. Fapp	Ff	Fg = FN	μ = Ff / FN

4. Drop the high and low Mu values and average the remaining three for the value of μ for PART B of the lab.
5. The force of friction for part B is F

Part B: Confirmation of the Work - Energy Theorem

• Collect three trials at three different heights, the mass of the bearing will remain constant.
• Measure the mass of the box & bearing together, this is used to find the weight and is equal to the normal force used to find the sliding frictional force.

Analysis:

1. There is a mechanical energy transformation along the length of the ramp, what causes this energy transformation?
2. Draw a free body diagram showing the forces and displacement for this mechanical energy transformation.
3. Is it an internal or external force?
4. Is Total Mechanical Energy, TME, conserved or not conserved
5. What is the result of the energy transformation?
6. There is a mechanical energy transformation along the length of the floor, what causes this energy transformation ball & box?
7. Draw a free body diagram showing the forces and displacement for this mechanical energy transformation.
8. Is it an internal or external force?
9. Is Total Mechanical Energy TME, conserved or not conserved?
10. What is the result of the energy transformation?

If your findings disagree with what you believe to be true based upon theory, you need to discuss possible sources of error.