ipad test

1. Name___________________________Pd_______
The Clicky Pen NRG Lab
A clicky pen exhibits many types of energy when used properly. We’ll take a look at a clicky pen to find out some information
about it using the Law of Conservation of Energy.
Before we start, you’ll need to find the mass of your pen. You’ll also calculate the weight while you’re at it…
Pen Mass:
kg Pen Weight:
N
In our first experiment, we’ll have the pen jump straight up
and see how far it goes. Click your pen so that the pen Trial Height Jumped (m) Potential Energy (J)
tip is out before each trial. Then, set the pen vertically
(pen tip pointing up) on the tabletop. Push down on the 1
pen and let it go. Measure how high the bottom of the
pen jumped off of the tabletop at least 10 times. Try to 2
measure only jumps where the pen stays pretty vertical
during the jump. If it rotates too far, your information 3
won’t be correct!
4
Calculate the potential energy of the pen at the top of each
jump. You can do this after all the experiments have 5
been completed. Also, find the average potential energy
of the pen for all the jumps. 6
•What part of the pen stores the energy to make it jump? 7
8
•How much energy did this part of the pen store before 9
the jump (on average)?
10
Avg. EP of Jump (J):
•Did that part of the pen do work on the pen? Why did you answer the way you did?
•According to the Law of Conservation of Energy, how much kinetic energy would the pen have right before it hits the table
(on average)?
•Using your answer to the last question, calculate the speed of the pen right as it started its jump. Remember that the pen
got its potential energy (at the top) from the kinetic energy it had right as it left the table!
OK, time for experiment #2. This time, we’ll try to find the speed of the pen another way. Click your pen once again, but this
time lay it horizontally on the tabletop, with the click button next to the wall or a book. Push the pen back against the wall
or book so that it will move horizontally across the tabletop. Let go and measure the distance the pen travels (from wall to
click button).
Repeat twice more (for a total of three trials). Record the three distances in the mini-chart on the back side of this sheet, and
calculate the average distance the pen traveled on the tabletop.

2. •Is the work you do to click the pen in experiment #1 the same as the work you had to do to click the pen in experiment #2?
Since the answer to that last question should have been yes, we can use your knowledge of motion and energy to find out the
force of friction acting on the pen as it slides along the tabletop.
Complete the following (some information may be found on the front side of the lab (you already found or calculated it…)).
Pen Mass:
kg Pen Start Speed: m/s
Pen Ending
Speed: m/s Pen Start EK:
J
Pen Ending EK:
J EK lost by pen:
J
Work done by
Distances (m)
friction: J Avg. Distance (m)
Once you have found the average distance your pen traveled, you can
find the force of friction. Since friction was the force that did work to
take away the pen’s kinetic energy, the work done by friction equals the force of friction times the distance the pen moved.
Using this information, find the average force of friction that acted on your pen.
Avg. force of
friction: N