# Basic force with static friction problem

• Ering
In summary, the skier, weighing 700 N, is moving down a 20-degree hill in a tuck position. The air resistance of 15 N and the coefficient of friction between the skis and the snow, 0.09, must be considered in determining the resultant downhill force acting on the skier. To find the resultant force, the force must be broken down into its x and y components, with the x-component being the resultant force in the right triangle.
Ering

## Homework Statement

A 70-kg skier is in a tuck position and moving down a 20-degree hill. Air resistance applies a resultant force of 15 N against the movement of the skier. The coefficient of friction between the skis and the snow is 0.09. What is the resultant downhill force acting on the skier?

## Homework Equations

Force = friction coefficient x normal force

## The Attempt at a Solution

I know you have to break down the force into its x and y components. So making a right triangle with the weight (~700 N: 70kg x 10 m/s2) as the hypotenuse and 70 degrees (90 - the given 20 degrees) as the angle. But after doing that, I'm not sure where to go from there. Is the resultant force also your x-component in the right triangle?

Ering said:
Is the resultant force also your x-component in the right triangle?
The resultant force in a given direction is the sum of all the components that are in that direction of the applied forces. What applied forces have components in the direction of interest?

## 1. What is static friction and how does it differ from kinetic friction?

Static friction is a force that opposes the motion of an object when it is at rest. It is caused by the microscopic roughness of surfaces and can vary in strength depending on the materials in contact. Kinetic friction, on the other hand, is the force that opposes motion when an object is already moving.

## 2. How can I calculate the force of static friction?

The force of static friction can be calculated using the equation Fs = μsN, where Fs is the force of static friction, μs is the coefficient of static friction, and N is the normal force acting on the object.

## 3. What factors affect the coefficient of static friction?

The coefficient of static friction can be affected by the roughness of the surfaces in contact, the weight of the object, and the type of material the surfaces are made of. It can also be affected by external factors such as temperature and humidity.

## 4. Can the force of static friction be greater than the force applied to the object?

Yes, the force of static friction can be greater than the force applied to the object, as long as the object remains at rest. Static friction will always be equal and opposite to the applied force, up to a certain maximum value determined by the coefficient of static friction.

## 5. How does static friction affect an object's motion?

Static friction plays a crucial role in keeping an object at rest. If the force applied to the object is not strong enough to overcome the force of static friction, the object will not move. However, once the applied force exceeds the maximum value of static friction, the object will begin to move and kinetic friction will take over.

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