• A 0.10kg ball dropped vertically from a
height of 1.0 meters above the floor
bounces back to a height of 0.80 meters.
The mechanical energy lost by the ball as
it bounces is how much?
• Where do you think the energy went?
• Why is it important to account for all the
energy?
Introduction
• Purpose
• Hypothesis
– Research the force of a bouncing ball.
• Physics concepts pertinent (related) to the
experiment
1. Finish calculating the PE, KE, and % loss.
2. Create a bar graph with ball type on the xaxis and percent energy loss on the y-axis.
Thinking time
• What did you learn?
(2 serious ideas)
• What could you do
to improve?
• Why would you be
confident in your
methods?
Conclusions
• The three think time questions
• RESTATE hypothesis – what did your
results show to support or detract?
• Any final thoughts
Mechani-what?
• Please revisit your
pulley lab data sheet.
Distance of Force (m)
Number of Supporting
Strands
Work Input (J)
MA
Efficiency
0.1
0.50
1
1.0
98%
0.22
0.59
2
1.8
83%
0.22
0.57
2
1.9
86%
0.32
0.54
3
2.9
90%
0.41
0.53
4
3.8
92%
Mechani-what?
• Which pulley arrangement
was the “easiest” to lift?
• Give your definition of
“easiest”.
Mechani-what?
Output force
Input force
W=F*d
If d goes up, what goes down?
What happens to the total work as a result?
Conclusion?
• Mechanical advantage has everything to do
with spreading (multiplying) the force over a
longer distance, and nothing to do with
lessening the work.