Formulas Just incase you need Fnet = ma ; Force(net) = mass x acceleration

F(g) = Force of gravity = mass x gravity = mg = weight
(g=9.8m/s2)
Ff = μkFN
Friction Force = coefficient of sliding (kinetic) friction x Force (normal)

Ff = μsFN
Friction Force = coefficient of static (not moving) friction x Force (normal)

1. If your mass is 120 Kg how many Newtons do you weigh on the moon? (gravity on moon is 1.63m/s2)

2. A 40 kg mass is pulled along a surface by a horizontal force of 300N. Friction on the mass is 30N. What is the acceleration of the mass?

3. A 24kg box initially at rest on a horizontal floor requires a 75N force to set it in motion. What is the coefficient of static friction between the box and the floor?

4. A 40kg mass is pulled by a horizontal force of 200N, with at a constant velocity. What is μk?

5. If the coefficient of friction between a 50kg box and the floor is 0.30, what horizontal force is required to move the box at a constant speed across the floor?

6. A drag race car engine produces a force of 50,000N. Air friction on the car is 5,000N. How long will it take the car to reach 50m/s?

7. A 300lb motorcycle travels at 60ft/s, locks the brakes and slides to a stop with μk = 0.5, what is the kinetic friction force?

8. If the motorcycle in problem 9 takes three seconds to stop, what distance did it take to stop?