Your name: _____________________
Please print this page, fill it in, and show it to your TF at the start of your lab session.
We're doing the MBL (Microcomputer-Based Lab) version of the Magnetic Forces and Potential Energy experiment. The interaction between the magnets in the experiment is similar to what would happen with a spring. We'll examine a spring experiment to become familiar with the concepts.
In general, in one dimension, the connection between a conservative force and the potential energy associated with it is:
| [Equation 1] F = -dU/dx | or | [Equation 2] U = - ∫ F dx |
In the first part of the experiment you will obtain the equation giving force as a function of distance between repelling magnets, and then use Equation 2 to obtain the corresponding potential energy. One way to verify the potential energy relationship is to roll a cart, with magnets attached, down a small incline toward a second set of magnets and keep track of all the different kinds of energy.
The simulation shows a similar experiment using a spring. Three curves are shown in the graph below the simulation. Identify each. The graphs are plotted versus position, not time. x = 0 is at the bottom of the ramp.
| The red curve is the: | gravitational potential energy | spring potential energy | kinetic energy |
| The blue curve is the: | gravitational potential energy | spring potential energy | kinetic energy |
| The green curve is the: | gravitational potential energy | spring potential energy | kinetic energy |
Assume there is no friction acting. If you added the three curves, what would you get?
| a horizontal line | a line that decreases as the object travels down the slope | a line that increases as the object travels down the slope |
If the object's position is X, measured from the bottom of the ramp along the incline, express the gravitational potential energy in terms of X and the angle of the incline:
Ug = mg_______