1. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
Use g = 10 m/s2
a) What happens to the fridge if you push on it with 460 N of force? Explain.
100 kg

2. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
Fridge is stationary, so you are pushing against STATIC Friction
FA = 460 N
Static Friction can provide UP TO 520 N of force
Ff = ?
But if I only push with 460 N of force then…

3. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
FA = 460 N
Ff = 460 N
…then friction only pushes back with 460 N of force

4. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
b) Suppose your friend helps by pushing with an additional 350 N. What happens to the fridge? Show Calculation.
100 kg

5. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
Now the applied force pushing to the right is 810 N
FA = 350 N
FA = 460 N
Which is bigger than the maximum Static friction (520N)
Ff = ?
But once it is moving, how much friction are the two of you pushing against?

6. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
Now the applied force pushing to the right is 810 N
FA = 350 N
FA = 460 N
Which is bigger than the maximum Static friction (520N)
Ff = 340 N
But once it is moving, how much friction are the two of you pushing against?

7. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
So Now calculate the net force and acceleration of the fridge…
FA = 350 N
FA = 460 N
810 N – 340 N = (100 kg )a
4.7 m/s2 = a
Ff = 340 N

8. A fridge resting on a cement garage floor has a static coefficient of friction of 0.52 and a kinetic coefficient of friction of The fridge has a mass of 100 kg.
FA = 520 N
c) What is the minimum force that you must push with to just get the fridge started moving? What force to push at const vel?
100 kg
FA = 340 N

9. A 4 kg Block gets pushed to the right and slides with a uniform acceleration for 35 m in 5.0 s from an initial velocity of 3.0 m/s. If µ = 0.30, what is magnitude of the force applied to the block by the outside push? (start with a force diagram)

10. A 4 kg Block gets pushed to the right and slides with a uniform acceleration for 35 m in 5.0 s from an initial velocity of 3.0 m/s. If µ = 0.30, what is magnitude of the force applied to the block by the outside push? (start with a force diagram)
Ff = µ mg
FA = ?
4 kg
Solve for acceleration:
FA – Ff = ma
FA = Ff + ma (algebra step)
d = 35 m
t = 5 s
v1 = 3 m/s
d = v1t +1/2 a t2
FA = µ mg + ma (substitution step)
FA = (0.3)(4kg)(9.8 m/s2) + (4kg)(1.6 m/s2)
FA = (11.76 N) + (6.4 N)
FA = N
a = 1.6 m/s2