NAME Section
PHYSICS 115 CYCLE 8
GROUP SUMMARY: CIRCULAR MOTION
1. Describe the model that you have learned and developed for uniform circular motion.
2. Applying the model: Using the pendulum provided (length L), make it swing around on a circular path such that its path traces out a circle of radius R.
a) Measure the period and the radius of the circle (this is most accurately done by measuring multiple periods).Period= R=
b) Use your measured values to calculate the speed of the pendulum bob. Describe your method of calculating v.
c) Calculate the centripetal acceleration.. acent=
d) Draw a free-body diagram of the pendulum as it moves. What direction does the net force point? Calculate its magnitude.
e) Which force (portion of a force) causes the centripetal acceleration?
f) Measure L and use this datum and the data you already measured to calculate q. q =
g) Determine Tradial and Tvertical. Tradial = and Tvertical=
h) Is your reasoning correct?: Use a spring scale to pull the pendulum bob out to an angle q.
i) Draw a free body diagram of the bob.
j) Compare the force measured by the spring scale to your calculation in g). Explain how this confirms your model (or doesn’t).
3. An automobile enters a curve of radius 45 m at a speed of 70 km/h. The driver maintains a constant speed throughout the turn. The curve is not banked and the coefficient of friction between the tires and the road is 0.8.
a) Does the car accelerate while turning? Explain.
b) Determine the magnitude and direction of the acceleration.
c) Draw a free body diagram of the car. This is most easily done from a frontal view perspective.
d) Which force causes the centripetal acceleration?
e) Will the automobile skid? Explain your answer.