Force of Friction on object on an incline

In summary, the friction force on a 3812.0 kg truck parked on an 18.1° slope is 11620 N. The friction force acts parallel to the incline and is determined by the component of gravity perpendicular to the incline. This can be calculated using the formula Ff = mgcos(theta), where theta is the angle of the incline.
  • #1
tascja
87
0

Homework Statement


A 3812.0 kg truck is parked on a 18.1° slope. What is the friction force on the truck?


Homework Equations



The Attempt at a Solution


So i set up a triangle with and then used:
weight of truck= (9.8 m/s^2 *3812 Kg) = 37367.6 N

sin(18.1) = (37367.6 N) /(-Ff)
Ff = -120246 N

Could someone explain why this is wrong.. I am thinking maybe i set up my triangle incorrectly, but i don't know how else i would draw it.. thanks in advance
 
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  • #2
Friction is based on the force normal to the incline, not normal to the horizontal.
 
  • #3
I thought friction went parallel to the incline?
 
  • #5
sorry but I am not following what your saying.. i don't know the materials so i can't find μ...
 
  • #6
You don't need μ in this case. The Frictional Force is what it balancing the truck's component of gravity down the incline. They just want you to find it. Not calculate it from the Normal force.
 
  • #7
ok so Ff = mgcos(theta) .. and then is 18.1 my angle?
 
  • #8
tascja said:
ok so Ff = mgcos(theta) .. and then is 18.1 my angle?

Is M*g*cosθ the component of gravity || to the incline?
 
  • #9
oh no then i would be mgsinθ = (3812 kg)(9.81 m/s^3)(sin18.1) = 1.162e4 N
 

Related to Force of Friction on object on an incline

1. What is the force of friction on an object on an incline?

The force of friction on an object on an incline is the force that opposes the motion of the object on the incline. It is caused by the contact between the object and the surface of the incline, and it acts in the opposite direction of the motion of the object.

2. How does the force of friction on an object on an incline affect its motion?

The force of friction on an object on an incline can either slow down or speed up the motion of the object, depending on the direction of the force and the angle of the incline. It can also cause the object to slide or roll down the incline if the friction force is not strong enough to oppose the gravitational force.

3. How is the force of friction on an object on an incline calculated?

The force of friction on an object on an incline can be calculated using the formula Ff = μN, where Ff is the force of friction, μ is the coefficient of friction, and N is the normal force. The coefficient of friction depends on the surfaces in contact and the normal force is the force perpendicular to the surface of the incline.

4. What factors affect the force of friction on an object on an incline?

The force of friction on an object on an incline is affected by the coefficient of friction, the normal force, and the angle of the incline. The coefficient of friction can vary based on the type of surfaces in contact, and the normal force can change depending on the weight of the object and the angle of the incline.

5. How can the force of friction on an object on an incline be reduced?

The force of friction on an object on an incline can be reduced by using materials with lower coefficients of friction, such as lubricants. It can also be reduced by decreasing the weight of the object or by decreasing the angle of the incline. Additionally, using wheels or rollers can reduce the friction force and allow for smoother motion on an incline.

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