Problem involving friction, with a mass being pulled up a slope

Thread starter Helena Durrant
Start date Jan 17, 2020
Tags

Dynamics Friction Mass Slope

In summary, friction is the force that opposes the motion of an object when it comes into contact with another surface. In the context of a mass being pulled up a slope, friction acts in the opposite direction of the motion, making it more difficult to pull the mass up. The weight of the mass, the roughness of the slope's surface, and the force used to pull the mass all affect the amount of friction present. To reduce friction in this scenario, one can use a smoother surface for the slope, apply a lubricant, or reduce the weight of the mass being pulled. Additionally, the angle of the slope also affects the force of friction, with steeper slopes resulting in greater friction and difficulty in pulling the mass up.

Jan 17, 2020

Helena Durrant

Homework Statement: A block sits on a slope that has an angle of 10◦ to the horizontal. There is a coefficient of
static friction µs = 0.3 between the block and the slope. You apply a force to the block in
an attempt to pull it up the hill. Calculate the angle to the horizontal at which you should
apply this force to maximise your chances of being able to make the block move up the
hill

Relevant Equations: limiting static friction equation

(The answer from the markscheme is 26.7)

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Jan 17, 2020

Doc Al

Mentor

Interesting problem. Where's your attempt?

1. What is friction and how does it affect a mass being pulled up a slope?

Friction is a force that opposes the motion between two surfaces in contact. In the context of a mass being pulled up a slope, friction acts in the opposite direction of the motion, making it more difficult for the mass to move up the slope.

2. How does the angle of the slope affect the amount of friction on a mass being pulled up?

The angle of the slope affects the amount of friction because it determines the normal force acting on the mass. The greater the angle, the greater the normal force, and therefore the greater the friction. This means that as the slope gets steeper, it becomes more difficult to pull the mass up.

3. What factors can affect the coefficient of friction in this scenario?

The coefficient of friction is affected by the nature of the surfaces in contact, the force pressing the surfaces together, and the roughness of the surfaces. In the case of a mass being pulled up a slope, the weight of the mass and the roughness of the slope will have the greatest impact on the coefficient of friction.

4. Can the mass ever reach a constant speed while being pulled up a slope?

Yes, it is possible for the mass to reach a constant speed while being pulled up a slope. This occurs when the force pulling the mass up the slope is equal to the force of friction acting against it. At this point, the net force on the mass is zero and it will continue to move at a constant speed.

5. How can we reduce the amount of friction on a mass being pulled up a slope?

The amount of friction on a mass being pulled up a slope can be reduced by using a lubricant, such as oil or grease, between the surfaces in contact. Additionally, reducing the weight of the mass or choosing a smoother surface for the slope can also decrease the friction. However, it is important to note that some friction will always be present and cannot be completely eliminated.