- #1
amazondog
- 20
- 0
Homework Statement
Hello, How do i find coefficient of friction knowing only mass, velocity and incline for a inclined plane?
A biker going up a hillMatterwave said:That's a very ambiguous question.
Mass of what? Velocity of what? Initial velocity or final velocity? Any information on acceleration? Is the velocity constant?
...
How do you find the force that is needed to go up the hill at the same velocity?
tramar said:You need to sum all the forces and get some equations to find mu. It would be easy if the cyclist was on flat land, then it would just be
[tex]\mu F_N-F_g=0[/tex]
But since he is on an incline you need to find the component of the gravitational force that is in the same direction as the normal force... and then plug that into find [tex]\mu[/tex].
Edit: You need to know the inclination angle of the hill. I don't know if that was given to you or not.
amazondog said:A biker going up a hill
Mass = 98.7kg
Constant velocity = 5.95m/s
So there is no acceleration.
amazondog said:Nasu, no i am not given an Fa.
All I have is: A biker rides up an 9.75degree hill at a constant speed of 5.95m/s. The biker and bicycle together have a mass of 98.7kg.
Find the coefficient..
What force does the system need to make the biker go up the hill at the same velocity..
What must the bikers power output be in order to go up the hill at the same speed.
Thanks guys I really appreciate it.
When the bike goes up the hill, the force that counteracts the weight component down the plane IS the static friction force between the rear tire and the road, which must be equal and opposite to the weight component down the plane. This is the only way a non-rocket powered vehicle can move ...if no friction, the wheels just spin in place. No matter what speed, this force is the same, but the power delivered by the cyclist will be different for different speeds. I don't see anything about the bike going down, you should post the question as written. You can't find the coefficient of friction, only the friction force, which I think it what the problem is asking for. Rolling and axle friction should be ignored, i guess.amazondog said:Sorry, my bad I re-wrote the question without it in front of me. It is going Down and it asks for the rest when it goes up. But how do i find the coefficient?
amazondog said:Sorry, my bad I re-wrote the question without it in front of me. It is going Down and it asks for the rest when it goes up. But how do i find the coefficient?
Thanks for clarifying the question. Your equation is incorrect, but you already answered part a in your post #6, so you must have done something right at that time. For part b, nasu has already given you some great hints in posts 14 and 18. Then move onto part c.amazondog said:umg = mgsin(theta ?
amazondog said:Ok, so the coefficient of velocity is tangent to the path. That makes sense.
almost. The friction force is not umgsin theta...your geometry and trig is a bit off..,, it's umg (_?__)theta.amazondog said:I think i GOT the force required to go up the mountain. Can someone please verify?
Fa - Ff - F// = 0
Fa - umgsin(theta) - mgsin(theta) = 0
Solve for Fa.
The coefficient of friction is a dimensionless number that represents the amount of resistance between two surfaces when they come into contact with each other. It is a measure of how difficult it is to slide one surface over the other.
The coefficient of friction can be determined by conducting experiments where the force required to move one surface over another is measured. By varying the applied force and measuring the resulting frictional force, the coefficient of friction can be calculated.
The coefficient of friction can be affected by several factors, including the nature of the surfaces in contact, the roughness of the surfaces, the presence of lubricants, and the normal force between the surfaces.
Yes, the coefficient of friction can change depending on the surrounding conditions. For example, adding a lubricant can reduce the coefficient of friction, making it easier for two surfaces to slide over each other.
Understanding the coefficient of friction is crucial in designing machines and structures that involve sliding or rolling contact between surfaces. It also plays a significant role in predicting the behavior of objects in motion and can help prevent accidents by determining the amount of force needed to move an object.