Friction between sled and rider

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In summary, Ginny is planning to ride her sled while her dog pulls her, but she may slide off due to a lack of understanding of physics. The sled has mass m and Ginny has mass M, with coefficients of static friction μ1 and μ2 for the sled and snow, and the sled and Ginny's snow pants, respectively. Ginny must have a certain minimum mass to prevent slipping off the sled, which can be found in terms of the other three variables. The normal force between the sled and the snow would be equal to the weight mg, and there are no vertical net forces on the sled since it is being pulled on level ground. Additionally, the vertical forces on the sled include the weight mg and the normal force n from the
  • #1
SillyYak

Homework Statement


Ginny has a plan. She is going to ride her sled while her dog Foo pulls her, and she holds on to his leash. However, Ginny hasn’t taken physics, so there may be a problem: she may slide right off the sled when Foo starts pulling.

The sled has mass m, and Ginny has mass M. The coefficient

of static friction between the sled and the snow is μ1, and μ2 is

the corresponding quantity for static friction between the sled and

her snow pants. Ginny must have a certain minimum mass so that

she will not slip off the sled. Find this in terms of the other three

variables.

i figure it would be M= m mu1/mu2 but the answer isn't being accepted, any help would be greatly appreciated

here was my logic Mgmu1= mgmu2 the g cancels out and you solve for big M, I am doing something wrong but don't know what, first time physics student here
 
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  • #2
SillyYak said:
Mgmu1= mgmu2
What is the normal force between the sled and the snow?
 
  • #3
would it not be equaled to mg the sled and snow have a zero angle
 
  • #4
SillyYak said:
would it not be equaled to mg the sled and snow have a zero angle
what are the vertical forces on the sled? Are they in balance?
 
  • #5
yes i believe so, she is having her dog pull her on level ground, the is no vertical net forces
 
  • #6
SillyYak said:
yes i believe so, she is having her dog pull her on level ground, the is no vertical net forces
I asked what they are.
 
  • #7
its mg and n there's no values stated in the problem
 
  • #8
SillyYak said:
its mg and n there's no values stated in the problem
I don't care about the values, I just wanted a descriptive list.
By "n" I assume you mean the normal force from the snow. What about the girl? Isn't she sitting on it?
 

FAQ: Friction between sled and rider

1. What causes friction between a sled and rider?

The force of friction between a sled and rider is caused by the roughness of the surfaces in contact with each other. As the rider sits on the sled, their weight creates a normal force which presses the two surfaces together. The microscopic bumps and imperfections on the surfaces create resistance as they rub against each other, resulting in friction.

2. How does friction affect the speed of a sled?

The friction between a sled and rider acts as a resistance force, slowing down the sled's speed. As the sled moves forward, the friction force acts in the opposite direction, causing a decrease in speed. The amount of friction depends on the weight of the rider, the roughness of the sled's surface, and the speed at which the sled is moving.

3. Can friction be reduced between a sled and rider?

Yes, friction between a sled and rider can be reduced by using smoother materials on the contact surfaces, such as lubricants or wax. These substances fill in the gaps between the surfaces and create a slippery layer, reducing the amount of friction. Additionally, reducing the weight of the rider can also decrease the amount of friction between the sled and rider.

4. How does friction affect the control of a sled?

The friction between a sled and rider can affect the control of the sled in several ways. If there is too much friction, it can be difficult to steer or change direction, making it harder to control the sled. On the other hand, if there is too little friction, the sled may slide too easily and be difficult to stop. Finding the right balance of friction is important for maintaining control of the sled.

5. How does the temperature affect friction between a sled and rider?

The temperature can have a significant impact on the friction between a sled and rider. In colder temperatures, the surfaces may become more brittle and have a higher coefficient of friction, leading to more resistance and slower speeds. In warmer temperatures, the surfaces may become more slippery and have a lower coefficient of friction, resulting in less resistance and faster speeds. It is important to consider the temperature when determining the amount of friction between a sled and rider.

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