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Solved: A bicyclist traveling with speed v = 4.2 m/s on a
Chapter 2, Problem 80GP(choose chapter or problem)
A bicyclist traveling with speed \(v=4.2 \ \mathrm{m} / \mathrm{s}\) on a flat road is making a turn with a radius \(=6.4 \ \mathrm{m}\). The forces acting on the cyclist and cycle are the normal force \(\left(\vec{F}_{N}\right)\) and friction force \(\left(\vec{F}_{f r}\right)\) exerted by the road on the tires, and \(m \vec{g}\), the total weight of the cyclist and cycle (see Fig. 8-56 ).
(a) Explain carefully why the angle the bicycle makes with the vertical (Fig. 8-56 ) must be given by \(\tan \theta=F_{f r} / F_{N}\) if the cyclist is to maintain balance.
(b) Calculate \(\theta\) for the values given.
(c) If the coefficient of static friction between tires and road is \(\mu_{s}\) = 0.70, what is the minimum turning radius?
Equation Transcription:
v=4.2 m/s
r=6.4 m
()
()
tan =
Text Transcription:
v=8.2 m/s
r=13 m
(vector F_N)
(vector F_fr)
m vector g
theta
tan theta = F_fr/F_N
mu_s
Questions & Answers
QUESTION:
A bicyclist traveling with speed \(v=4.2 \ \mathrm{m} / \mathrm{s}\) on a flat road is making a turn with a radius \(=6.4 \ \mathrm{m}\). The forces acting on the cyclist and cycle are the normal force \(\left(\vec{F}_{N}\right)\) and friction force \(\left(\vec{F}_{f r}\right)\) exerted by the road on the tires, and \(m \vec{g}\), the total weight of the cyclist and cycle (see Fig. 8-56 ).
(a) Explain carefully why the angle the bicycle makes with the vertical (Fig. 8-56 ) must be given by \(\tan \theta=F_{f r} / F_{N}\) if the cyclist is to maintain balance.
(b) Calculate \(\theta\) for the values given.
(c) If the coefficient of static friction between tires and road is \(\mu_{s}\) = 0.70, what is the minimum turning radius?
Equation Transcription:
v=4.2 m/s
r=6.4 m
()
()
tan =
Text Transcription:
v=8.2 m/s
r=13 m
(vector F_N)
(vector F_fr)
m vector g
theta
tan theta = F_fr/F_N
mu_s
ANSWER:
Step 1 of 3
(a)
In order not to fall over, the net torque on the cyclist about an axis through the CM and parallel to the ground must be zero. Consider the free-body diagram shown. Sum of the torque about CM, with counter clockwise as positive, and the net sum is equal to zero.