Question

1. A sled is being pulled by a dog on a horizontal surface. Are the following statements true or false? Explain your answer
   1. If there is no friction between the sled and the surface (dog has friction) the sled will move no matter how little force the dog applies on the sled.
   2. When there is friction the coefficient of static friction remains the same as the force applied by the dog increases until the sled starts to move.
   3. Once the sled starts to move and the dog keeps pulling the coefficient of kinetic friction remains constant regardless of the amount of force applied by the dog.
   4. Once the sled starts to move and the dog keeps pulling with a constant force the net force acting on the sled also remains constant.
2. A skier slides down a straight ski trail with an inclination of 22⁰. The coefficient of kinetic friction between the skis and the slope is 0.08.
   1. What is the acceleration of the skier down the slope?
   2. Because of the friction the skier will not slide at all if the slope inclination is small. What must the minimum angle of inclination of the slope for the skier to slide down if the maximum static coefficient of friction is 0.1?

Answer 1