Yikes, I (Centripital Motion/Forces/Friction)

• tectactoe
In summary, the conversation is about a problem involving finding the smallest radius for an unbanked track for a bicyclist to travel at a speed of 24 km/h and a coefficient of static friction of 0.30. The person asking for help is unsure of the correct equation to use and how to find the radius with the given values, and another person provides guidance on using the equation for the force required to accelerate an object in a circle and the force due to friction. The solution is then given as r = (v^2)/(mu)*g.
tectactoe
I can't solve this problem for the life of me, and I don't know how to begin even. If someone could explain the procedure, I'd be more than grateful... it can't be THAT hard, I just have no idea where to start. =[ Thanks.

"What is the smallest radius of an unbanked (flat) track around which a bicyclist can travel if her speed is 24 km/h and the coefficient of static friction between tires and track is 0.30?"

tectactoe said:
I can't solve this problem for the life of me, and I don't know how to begin even. If someone could explain the procedure, I'd be more than grateful... it can't be THAT hard, I just have no idea where to start. =[ Thanks.

"What is the smallest radius of an unbanked (flat) track around which a bicyclist can travel if her speed is 24 km/h and the coefficient of static friction between tires and track is 0.30?"

This should be posted in the homework subforum. As for how to solve it, first write down what you know to show you are making some effort. Do you know the equation for the force required to accelerate an object in a circle at a given radius?

"What is the smallest radius of an unbanked (flat) track around which a bicyclist can travel if her speed is 24 km/h and the coefficient of static friction between tires and track is 0.30?"

v = 24 km/h
us = 0.30

I know

(us)(Fn) = m(v^2/r)

but I don't know if that's the right equation, nor how to find r with only these values.

x_x

tectactoe said:
"What is the smallest radius of an unbanked (flat) track around which a bicyclist can travel if her speed is 24 km/h and the coefficient of static friction between tires and track is 0.30?"

v = 24 km/h
us = 0.30

I know

(us)(Fn) = m(v^2/r)

but I don't know if that's the right equation, nor how to find r with only these values.

x_x

You´ll also need the equation for the force due to friction. Once you have these two equations the rest is just algebra.

ok buddy, this is more of a conceptual question. There are only 2 forces acting on the object, the normal force = to its weight, and the Friction force.

=> Sum of Forces in x has to = Friction force

=> ma = -m*(v^2)/r = -(mu)*m*g
Note: negative sign since the vector points inward toward the center of the circle.

Solve and u get
r = (v^2)/(mu)*g

Hope u got it, any more question?

just post them here,

ZPower

What is centripetal motion?

Centripetal motion is the movement of an object in a circular path around a fixed point, caused by a force acting towards the center of the circle.

What are some examples of centripetal forces?

Some examples of centripetal forces include the gravitational force that keeps planets in orbit around the sun, the tension force in a swinging pendulum, and the friction force between a car's tires and the road as it makes a turn.

What is the relationship between centripetal force and centripetal acceleration?

The centripetal force is the force that causes an object to move in a circular path, while the centripetal acceleration is the acceleration towards the center of the circle. These two are directly proportional to each other and can be calculated using the formula F = ma, where F is the centripetal force, m is the mass of the object, and a is the centripetal acceleration.

How does friction affect centripetal motion?

Friction is a force that opposes the motion of an object, and it can affect centripetal motion by reducing the speed of the object or changing its direction. For example, when a car turns, the friction force between its tires and the road causes it to slow down and change direction.

What is the difference between centripetal and centrifugal force?

Centripetal force is the force that keeps an object moving in a circular path, while centrifugal force is the apparent outward force experienced by an object in circular motion. Centrifugal force is not a real force, but rather a result of inertia, which causes objects to resist changes in their motion.

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