Solving problems involving friction force

What is the coefficient of static friction if it takes 44 N of force to move an 86-N box on a horizontal surface?

• 0.78

• 0.51

• 0.78 N

• 0.58 N

A 220-kg crate is pushed horizontally with a force of 700 N. If the coefficient of kinetic friction is 0.20, calculate the acceleration of the crate.

• 1.02 m/s²

• 1.22 m/s²

• 1.42 m/s²

• 1.62 m/s²

What is the force of friction between a 950-N block of ice and the horizontal ground if μ = .12?

• 65 N

• 226 N

• 175 N

• 114 N

You are driving a 1200.0 kg car at a constant speed of 14.0 m/s along a straight, level road. As you approach an intersection, the traffic light turns red. You slam the brakes. The car’s wheels lock, the tires begin skidding, and the car slides to a halt in a distance of 25.0 m. What is the coefficient of kinetic friction between your tires and the road?

• 0.400

• 2.5

• 3.92

• 0.25

Your family just had a new refrigerator delivered. The delivery man has left and you realize that the refrigerator is not quite in the right position, so you plan to move several cm. If the refrigerator has a mass of 88 kg and the coefficient of kinetic friction is 0.13 and the coefficient of static friction is 0.21, how hard do you have to push the refrigerator to start moving?

• 12 N

• 181 N

• 18 N

• 112 N