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Lab Activity: Hot Wheels Energy Transformation
Materials: Hot wheels track, ring stand for top of track, hot wheels car, 3D printed sled, meter stick.
Purpose: Determine the relationship between start height and the corresponding potential energy, velocity and
stop distance (and corresponding work done in stopping) of a hot wheels car.
Procedure: Set up the track with 5 sections of track at a shallow angle from horizontal. Create a data table that
has 4 starting points for the hot wheels car.
Record the mass of the car _____________________ Mass of 3D printed sled ____________________
For placement of the car, put the center of the car at the starting points selected. Measure the vertical distance
up to the bottom of the track for each starting point.
Starting
height
Potential
energy
mgh
Velocity of
car
(calculated)
Trial 1
Distance slid
Trial 2
Trial 3
Average
Use the following equation (assuming no friction or air resistance for the car coming down the track) to
calculate the velocity of the hot wheels car:
2
The kinetic energy at the bottom – (½)mv – should be close to the potential energy – mgh –
of the car at the start point.
What would make it different? Would it be more, or less than the potential energy at the start?
Show how you would you would solve for the velocity using those two equations, assuming the
energy at the top equals the energy at the bottom (energy is conserved).
Solving for v, enter the calculated velocity value in the table above.
Now do three trials at each height, and measure the distance the car/sled combination slides across the table.
Enter in the table above, and calculate the average value.
Copy the corresponding data from the previous table into the first four columns of this table:
Starting
height
Potential
energy
Using the equation:
stop.
Velocity of
car
(calculated)
Distance slid
Average
Work
Ff
Work done
on car by Ff
Vf2 = Vi2 + 2ad, calculate the acceleration of the car/sled combo while coming to a
Would you expect the acceleration to be different for different velocities?
What force provides the acceleration while the car is slowing down?
Use this equation to calculate the value of that force. Draw a free body diagram showing the forces on the
car/sled as it’s sliding to a stop.
Ff = Fnet = ma
What is the coefficient of friction for the car/sled and table surface? (You’ll need this for a later lab!!)
Ff /FN = μ Remember that the normal force is the weight of the car/sled.
Not its mass.
Calculate the work done on the car while stopping it. (is it positive or negative?)
.
Make a graph of the work done in stopping the car versus the starting potential energy of the
car as you changed the starting heights for the car. Be sure to include a title, label the axes, and
include the units. Enter the data points, and draw a trend line.
Lab Activity: Hot Wheels Spring Launcher Energy Transformation
Materials: Hot wheels car, spring launcher, hot wheels car, 3D printed sled, meter stick.
Purpose: Determine the energy in the spring launcher by measuring the stopping distance of a hot wheels car
coming off of it. Also find the spring constant for the spring in the launcher.
Procedure: Set up the launcher with the 3D printed sled in front of it. Create a data table for 3 trials.
Record the mass of the car _____________________ Mass of 3D printed sled ____________________
Total mass, converted to kilograms: (keep at least 3 digits after the zeroes) ___________________
From the previous hotwheels lab – what was the coefficient of friction for the car/sled and table surfaces?
μ = ___________ FN = -mg = ________
Ff = μ• FN = __________
Place the car on the launcher, with the sled just in front of it. Find
the average distance the car/sled slides after leaving the launcher.
The kinetic energy of the car coming off the ramp should be
close to the amount of (negative) work that friction did on the
car/sled combination. Calculate the average work done in
stopping the car.
Trial
Distance slid, in meters
1
2
3
Average
Work = Ff • distance = _______________
KE = ____________
What was the velocity of the car coming off the launcher?
½mv2 = KE
.
Measure the distance the spring is compressed on the launcher: x
What is the spring constant for the launcher? (Solve for k below)
PEspring = ½kx2
= ________________ m