Potential (stored) Energy can be converted to Kinetic (applied) Energy and back again. We will use an inclined plane to convert the potential energy of a ball at the top of the ramp to a ball in motion at the bottom and then compare the potential energy we started with to the kinetic energy it was converted to when the ball was released.

Formulas: PE = mgh KE = 1/2mv2

Note: You will have to make a couple of
conversions along the way:

Height must be given in meters, not centimeters.
Convert it by dividing by 100.

Mass must be given in kg, not grams.
Convert it by dividing by 1000.

Gravity (here on Earth anyway) = 9.8 m/s2

Procedure

Measure the mass of the marble and the
ball bearing and record these on the data table.

Calculate the PE of each ball at each
height in the data table.

Set up the ramp on the ringstand (as in
the velocity lab) to the height specified in the data table.

Measure out the distance of the “track”
from the end of the ramp to the “finish line” and record this on your data
table.

Let the ball roll down the inclined plane
and record the time it takes to travel the track.

Calculate the velocity for each run of
the balls.

Calculate the KE to finish out the data
table.

Results

Ball Bearing
Marble

Height (m)0.1 0.2
0.3 0.1
0.2 0.3

Mass of Ball (kg)_____ _____ _____ _____ _____ _____

Distance traveled (m)_____ _____ _____ _____ _____ _____

Time to travel (s)_____ _____ _____ _____ _____ _____

Velocity of ball (m/s)_____ _____ _____ _____ _____ _____

PE (J)_____ _____ _____ _____ _____ _____

KE (J)_____ _____
_____ _____ _____
_____

Graph:

Make a graph of the PE and KE vs. height.

Height (cm) = x-axis

Energy (J) = y-axis

Plot the PE data for the ball bearing
with a solid round point.

Plot the PE data for the marble with a
hollow round point.

Plot the KE data for the ball bearing
with a solid square point.

Plot the KE data for the marble with a
hollow square point.

Conclusions

How did the balls’ potential and kinetic
energy change as the height of the inclined plane changed?

Which had more potential energy, the marble
or the ball bearing?

Which had more kinetic energy?

What are some potential sources of error
in this design?

What does this say about conservation of energy?

Copyright Alexplorer. Some items taken from or adapted from other materials. This page is free for use in a classroom setting.

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