Buggé: Energy 10
1. Galileo’s Pendulum A pendulum bob attached to a string swings in a vertical plane. A nail
can be placed at different locations along the path of the string. You pull the bob to the side
so it starts at a height h above the straight down position. When the bob swings down and the
string meets the nail, to what maximum height will the bob rise on the other side?
2. Four Tracks Four identical steel balls, released simultaneously from rest, will roll down
ramps that have different shapes but are of the same height.
a. Based off of our explanations and understanding of energy predict which ball will
reach the bottom of the ramp first.
b. Predict how far each ball will travel once it leaves the ramp.
3. Energy Skate Park Explore the energy skate park simulation. Be comfortable moving your
reference level and creating bar charts for gravitational potential and kinetic energies at
different points in the skater’s path.
The following problems are based on data from the 2010 Winter Olympics:
4. Speed Skating The Czech Republic’s Sablikova (50 kg) won the women’s 3000 m speed
skating finals in 4 minutes, 2 seconds. The Netherlands Kramer (60 kg) won the men’s 5000
m speed skating finals in 6 minutes, 14 seconds. Which athlete generates more power?
5. Curling You happen to wander over to the qualifying rounds for Curling! Here, contestants
throw a 20 kg rock down a 50 m lane in an attempt to have it stop on a target 3.7 m in
diameter at the other end. The rock must touch a part of the target in order to earn points.
You have up to 11 m on the track to release the stone (kind of like the foul line in bowling).
If the coefficient of friction between the ice and the rock is 0.2, at what speed does an
Olympian have to release the stone to get it to land within the target? Why do you think
curlers ‘sweep’ in the path of the stone on its way down the track?
6. Men’s Mogul Skiing Alex Bilodeau won the men’s Mogul ski event (skiing over mounds of
snow) to give Canada their first gold medal at the Vancouver Olympics! The 68 kg athlete
skied down the 28 degree inclined course a distance of 250 meters in 24 seconds. How much
work did the Earth do on Bilodeau while he was skiing? How much power did he generate
due to his interaction with the Earth during this medal winning run? How fast was he skiing
at the bottom of the hill? What assumptions did you make?
7. Pose a problem Describe a real-life situation in which an external force does the following:
a. Positive work on a system
b. Positive work on a system but with a value that is less than that in part (a)
c. Negative work on a system
d. Zero work, even though an object in the system moves.
Buggé: Energy 10
8. Bar Chart Jeopardy The bar chart below describes a real process. Fill in the table that
follows to describe the possible processes. Do not solve for anything.
Bar chart
KiUgiUsi W
Draw an initialfinal sketch of a
process that might
be described by the
bar chart.
Describe the
process in words.
Kf UgfUsf∆Uint
0
9. Roller Coaster Problems (on board in classroom)
Use the bar chart to
apply in symbols the
generalized work-energy
equation to the process.