Coefficient of Friction of object sliding down ramp

In summary, the coefficient of friction of the incline in this problem is approximately 0.23. This was found by using the formula f = u*Fn, where f is the friction force, u is the coefficient of friction, and Fn is the normal force. The normal force was calculated to be 78.48N by using the given mass, angle, and gravitational acceleration. The friction force was given to be 18N, and from there, the coefficient of friction was found to be 0.23. This information was needed to solve a bonus question in a physics class.
  • #1
grr_physics
16
0
Coefficient of Friction of object sliding down ramp.. need help!

Homework Statement


An 10.0kg object slides down an inclined plane that is 10.0m in length. THe height of the incline is 6.0m and the speed of the object at the bottom is 9.0 m/s.
What is the coefficient of friction of this incline?
So far I found:
Energy lost due to friction= 183.6 J
Force of friction= 18 N

Can someone show me how to find the coefficient of friction ASAP please? This is an advance question in my class for bonus marks & I NEED those bonus marks.
 
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  • #2
How to find coefficient of friction of object sliding down ramp? Please Help!

Homework Statement


An 10.0kg object slides down an inclined plane that is 10.0m in length. THe height of the incline is 6.0m and the speed of the object at the bottom is 9.0 m/s.
What is the coefficient of friction of this incline?
So far I found:
Energy lost due to friction= 183.6 J
Force of friction= 18 N

Can someone show me how to find the coefficient of friction ASAP please? This is an advance question in my class for bonus marks & I NEED those bonus marks.
 
  • #3


oh yeah i also found the angle at the bottom is 36.869... degrees if that helps.
 
  • #4


oh yeah i also found the angle at the bottom is 36.869... degrees if that helps
 
  • #5


The formula relating friction force and coefficient of friction is: f = u*Fn, where f is the friction force, u is mu(coefficient of friction), and Fn is the normal force.
 
  • #6


how do I find the normal force?
I just started physics 30 & totally forget everything... :(
 
  • #7


You have the friction force, so now what formula relates the friction force with the coeff. of friction??
 
  • #8


u= F/ Fn but i don't know what my Fn is?
 
  • #9


okay i did tried this:

Fn= (10.0kg)(cos(36.869...degrees))(9.81)
= 78.48...N

u=F/Fn
=0.22935...

is this correct?
 
  • #10


the normal force is the force the object exerts on whatever surface it rests. In other words, its mass(i.e. m*g)
 
  • #11


Ok, Fn is the normal force acting on the object perpendicular to the incline. Call that direction the 'y' axis, and the direction along the incline will be the 'x' axis. In the y direction, there is no acceleration, so Newton's first law applies. Identify all the forces or force components in the y direction (what are they?) and set their sum equal to 0 to solve for Fn .
 
  • #12


okay i did tried this:

Fn= (10.0kg)(cos(36.869...degrees))(9.81)
= 78.48...N

u=F/Fn
=0.22935...

is this correct?
 
  • #13


I don't know the other forces, only the top mechanical energy & bottom mechanical energy
 
  • #14


grr_physics said:
okay i did tried this:

Fn= (10.0kg)(cos(36.869...degrees))(9.81)
= 78.48...N

u=F/Fn
=0.22935...

is this correct?
You didn't need the hint, nice job! Just be sure to round off the coefficient to one (or 2 at the most) decimal places.
 
  • #15


grr_physics said:
I don't know the other forces, only the top mechanical energy & bottom mechanical energy
Oh, how did you find Fn if you didn't know the other force acting? Did you look it up somewhere?
 
  • #16


i figured out the 18 N in class but I don't remember how but thanks a bunch for the help, even though u say I didn't need the hint, your hint made me think & brought back everything! =)
 
  • #17


Yes, that's correct.
 
Last edited:

What is the coefficient of friction?

The coefficient of friction is a measure of the amount of friction between two surfaces in contact. It is a dimensionless number that represents the ratio of the force of friction between the two surfaces to the normal force pressing them together.

How is the coefficient of friction calculated?

The coefficient of friction can be calculated by dividing the force of friction by the normal force. It can also be calculated by measuring the slope of a graph of friction force vs. normal force.

What factors affect the coefficient of friction?

The coefficient of friction is affected by the nature of the two surfaces in contact, their roughness, the force pressing them together, and the presence of any lubricants or other substances between them.

Why is the coefficient of friction important?

The coefficient of friction is important because it helps us understand and predict the behavior of objects in contact with each other. It is also crucial in engineering and design, as it affects the efficiency and safety of machines and structures.

How does the coefficient of friction affect an object sliding down a ramp?

The coefficient of friction affects an object sliding down a ramp by determining the amount of resistance or friction the object experiences as it moves down the ramp. A higher coefficient of friction means the object will slow down more quickly, while a lower coefficient of friction allows the object to slide more easily.

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