Finding the Coefficient of Friction?

Therefore, the force of gravity acting on the sled is equal to the normal force. Before the boy pulls on the sled, the normal force is equal to the weight of the sled, which is 5kg x 9.8m/s^2 = 49N. After the boy pulls on the sled, the normal force decreases to 5N, since the force of gravity remains the same but the horizontal force decreases the normal force. In summary, the coefficient of friction between the sled and the ice is 0.12, the force of gravity acting on the sled is equal to the normal force, and the normal force decreases from 49N to 5N after the boy pulls on the sled.
  • #1
Brodo17
18
0
A boy pulls a sled of mass 5kg with a rope that makes an angle of 60 degrees w/ respect to the horizonal surface of the frozen pond. The boy pulls on the rope with a force of 10N and the sled moves with constant velocity. What is the coefficient of friction between the sled and the ice?


F=ma
f=mewFN


First I found the horizonatal force that the boy is exerting on the sled:
Cos60 X 10 = 5N
Then I thought that since the acceleration is constant that the sum of the forces must be zero. This would mean that the frictional force must be equal to the applied force of 5N

So, I said 5N = mew (5kg X 9.8)
And I found mew to be .102

However apparently the answer is .12

Thanks!
 
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  • #2
What is the force of gravity acting on the sled?
What is the normal force before the boy pulls on the sled? What about after?

I hope these help.
 
  • #3
Both forces in the x and y direction must sum to 0, since its in constant velocity.
 

Related to Finding the Coefficient of Friction?

1. What is the coefficient of friction?

The coefficient of friction is a measure of the amount of resistance between two surfaces in contact with each other. It is represented by the symbol μ and is typically a value between 0 and 1, with lower values indicating less resistance and higher values indicating more resistance.

2. How is the coefficient of friction determined?

The coefficient of friction is determined by conducting a series of experiments in which one surface is dragged or pushed against another surface at a constant speed. The force required to maintain this constant speed is measured and used to calculate the coefficient of friction.

3. What factors can affect the coefficient of friction?

The coefficient of friction can be affected by several factors, including the roughness of the surfaces, the materials of the surfaces, the temperature, and the presence of any lubricants or contaminants on the surfaces.

4. Why is knowing the coefficient of friction important?

Knowing the coefficient of friction is important in many areas of science and engineering. It can help in designing and improving machines and structures, predicting the performance of materials, and understanding the behavior of objects in motion.

5. How can the coefficient of friction be reduced?

The coefficient of friction can be reduced by using lubricants between the surfaces, using materials with lower coefficients of friction, or by making the surfaces smoother. In some cases, adjusting the temperature or pressure between the surfaces can also affect the coefficient of friction.

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