Charlie Brown’s Wind Up
Objective 1 (E6): To determine the tangential speed and angular speed of the swings.
SUGGESTED PROCEDURE: Pace or measure a distance near the swings that is the same distance as the radius of
the circular path made by the swings at full speed. Calculate the length of the path followed by the swings and
time a complete revolution.
APPARATUS: Stopwatch, known pace or tape measure.
DATA:
Radius of path of swings:
Time of one complete revolution:
__________ m
__________ s
RESULTS:
Tangential speed of swings:
Angular speed of swings
__________ m/s
__________ rev/min
__________ radians /s
Objective 2 (E7, E10): To calculate the centripetal acceleration of the swings using three methods.
SUGGESTED PROCEDURE:
a) Using an astrolabe (horizontal accelerometer) or other angle measuring device, measure the angle that the
chain to the seats makes with the vertical and calculate centripetal acceleration as a function of gravity and
the angle;
b) Use speed and radius results from OBJECTIVE 1 to calculate centripetal acceleration;
c) Use a vertical accelerometer held parallel to the chain while riding the swings to determine the centripetal
acceleration of the swings;
APPARATUS:
Astrolabe (horizontal accelerometer)
Vertical accelerometer (spring accelerometer)
DATA & RESULTS:
a)
Angle between chain and the vertical:
__________ m/s2
Centripetal acceleration:
b)
c)
__________ degrees
Speed: _________ m/s ;
Radius:
__________ m
Centripetal acceleration
__________ m/s2 (a = v2/R)
Spring Accelerometer reading: __________ m/s2
Centripetal acceleration:
__________ m/s2
CONCLUSIONS:
Objective 3 (E8):
To calculate the total tension in the chain due to presence of rider.
SUGGESTED PROCEDURE: Using rider's weight, calculate tension in the chain due to gravity and centripetal
acceleration.
APPARATUS: None if all the above data has been collected.
DATA: Your mass _________ kg + Mass of swing(15 kg):
Resultant acceleration from OBJECTIVE 2c:
RESULTS:
Total tension on chains using mass of rider and seat
and the accelerometer reading from OBJECTIVE 2c:
_________ kg
_________ m/s2
_________ N
Objective 4 (E6, E11, E12, E13):
To calculate the work done from the start of ride until the ride reaches full
speed assuming the kinetic energy and potential energy at the start are each zero for a single rider.
SUGGESTED PROCEDURE: Using rider's mass, the tangential speed from OBJECTIVE 1, estimate change in
height as the ride reaches full speed.
APPARATUS: None if all the above data has been collected
DATA: Your mass _________ kg + Mass of swing(15 kg):
Tangential speed from Objective 1:
Estimated change in height:
RESULTS:
Change in kinetic energy:
Change in potential energy
Work done on a rider:
_________ kg
_________ m/s
_________ m
_________ J
_________ J
_________ J
Objective 5 (E16): To calculate the power required for a spinning rider from start to full speed.
SUGGESTED PROCEDURE: Use the work obtained in OBJECTIVE 4 and the time needed from start to full speed.
APPARATUS: Stopwatch
DATA: time from start to full speed
_________ s
RESULTS: Power required:
_________ W
Power required:
_________ hp