®
M o d e l N o . M E - 6 8 4 3
Se n s o r - b a s e d E x p e r i m e n t
5
Spring Compression
Release
4.
Press the
ZERO
or
TARE
button on the force sensor.
5.
Start data recording.
6.
Slowly pull back with the force sensor until the spring is
almost
completely com-
pressed.
Note: Have your partner hold the track to prevent it from slipping, but be careful not to block
the motion sensor.
7.
Stop data recording.
8.
Determine
k
from the slope of the
F
x
versus
x
graph.
9.
Measure the area under graph. This area equals the work,
W
, that you did on the
spring.
10.
From the graph, determine the displacement (or
change
in position) of the end of
the spring.
11.
Use Equation 3 to calculate
U
spring
, the potential energy stored in the spring after
you compressed it.
12.
Compare
W
to
U
spring
. Do both values have the same (or equivalent) units? What
is the percent difference?
13.
Repeat steps 1 through 8 to determine the spring constants of all three springs.
Untie the string from the launcher shaft for the next part.
Spring Potential Energy and Kinetic Energy
In this part, you will study the relationship between the potential energy initially
stored in the spring and the kinetic energy of the cart just after launch.
1.
Place a second end stop on the track about 8 cm behind the first end stop.
2.
Place the cart on the track with the launcher shaft through the hole in the first end
stop. Position the cart so that the spring is touching the end stop but not com-
pressed.
3.
Start data recording.
4.
Wait a few seconds (to let the sensor measure the uncom-
pressed position). Push the shaft through both and stops and
put the release pin into the shaft. Let the pin rest against the
second end stop and wait a few more seconds (to let the sen-
sor measure the compressed position).
Important: In the next step, have your partner catch the cart before it
hits the motion sensor.
5.
Pull out the release pin with a quick jerk to launch the cart
6.
Stop data recording.
7.
Determine the spring compression from the graph of position
versus time.
