Friction, inclined slope

In summary, a 40kg wheel is rolling down a 30-degree inclined hill and reaches a speed of 5m/s before falling on its side and sliding down the hill. The first question asks how long it will take for the wheel to come to a complete halt if the coefficient of friction is 1.00, and the second question asks if the coefficient of friction is 0.500, will the wheel still stop and why. The problem arises from the wheel falling over after reaching 5m/s and encountering frictional force. To calculate the net force, one must subtract the parallel force (mg sin theta) from the friction force (coefficient*m*g). The initial velocity may not have an effect on the acceleration since it
  • #1
Lalasushi
11
0
hi peeps, can u guys help me with this question:

A wheel weighing 40kg is rolling down a hill, inclined at 30 degrees. After reaching a speed of 5m/s, the wheel falls over on its side and begins sliding down the hill.
1. if the coefficient of friction for the sliding wheel is 1.00, independent of the wheel's velocity, how long will it take the wheel to come to a complete halt?
2. if the coefficient of friction is instead 0.500, will the wheel still stop? why or why not?

im having trouble with the thing about the wheel becoming sliding after reaching 5m/s. i would really appreciate some help.

thanx
 
Physics news on Phys.org
  • #2
What exactly is the problem you're having? An object sliding down an inclined surface at 5 m/s encounters a frictional force. When the coefficient of friction is 1, what do you know about the net force on the wheel?
 
  • #3
like you said, the wheel falls over after 5 m/s
like, if i were standing around and fell over.
on my face

a wheel on its side is just a round thing with rubber on it's sides; it's going to slide around, not roll, correcto?
 
  • #4
I have the same problem. What I did was get the parallel force (mg sin theta) and subtract that with the friction force (coefficient*m*g) to get the net force. Then I set this equal to ma to get the acceleration. But I'm wondering if the initial velocity has any play in calculating the acceleration. When I imagine it visually it seems the initial velocity would have increased the acceleration. But in my formulas, v0 didn't appear at all, unless it was somehow canceled out?
 
  • #5


Hi there,

Friction is a force that opposes motion between two surfaces in contact. In this scenario, the wheel is experiencing friction as it rolls and slides down the inclined slope. The coefficient of friction is a measure of the friction force between two surfaces, and is dependent on factors such as the materials in contact and the roughness of the surfaces.

1. To calculate the time it takes for the wheel to come to a complete halt, we can use the equation:
v = u + at
Where:
v = final velocity (0 m/s)
u = initial velocity (5 m/s)
a = acceleration (determined by the coefficient of friction and the angle of the incline)
t = time

To find the acceleration, we can use the equation:
a = μgcosθ
Where:
μ = coefficient of friction (1.00)
g = acceleration due to gravity (9.8 m/s^2)
θ = angle of the incline (30 degrees)

Substituting these values into the first equation, we get:
0 = 5 + (1.00)(9.8)(cos30)t
Solving for t, we get:
t = 0.51 seconds
Therefore, it will take the wheel approximately 0.51 seconds to come to a complete halt.

2. If the coefficient of friction is instead 0.500, we can use the same equations to calculate the time it takes for the wheel to stop. However, in this case, the acceleration will be:
a = (0.500)(9.8)(cos30) = 2.45 m/s^2
Substituting this value into the first equation, we get:
0 = 5 + (2.45)t
Solving for t, we get:
t = 2.04 seconds
Therefore, it will take the wheel approximately 2.04 seconds to come to a complete halt.

To answer your question about the wheel becoming sliding after reaching 5m/s, this is due to the increase in kinetic energy as the wheel gains speed. Once the wheel reaches a certain speed, the friction force may not be enough to keep it rolling and it will start to slide.

I hope this helps! Let me know if you have any further questions.
 

1. What is friction?

Friction is a force that resists the relative motion between two surfaces in contact.

2. How does an inclined slope affect friction?

An inclined slope increases the amount of friction between two surfaces, as the force of gravity acts upon the objects and increases the normal force between them.

3. What factors affect the amount of friction on an inclined slope?

The amount of friction on an inclined slope is affected by the weight of the objects, the roughness of the surfaces, and the angle of the slope.

4. How does friction on an inclined slope affect the speed of an object?

Friction on an inclined slope can slow down the speed of an object, as it works against the force of gravity pulling the object down the slope.

5. How can friction be reduced on an inclined slope?

Friction on an inclined slope can be reduced by using a lubricant between the surfaces or by decreasing the angle of the slope.

Similar threads

  • Introductory Physics Homework Help
Replies
14
Views
2K
  • Introductory Physics Homework Help
Replies
7
Views
839
  • Introductory Physics Homework Help
Replies
32
Views
2K
  • Introductory Physics Homework Help
Replies
27
Views
5K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
33
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
12
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
Back
Top