A block weighing 80N rests on a plane inclined at 20 degrees to the horizontal. The coefficient of static friction is 0.25, while the coefficient of kinetic friction is 0.15.(adsbygoogle = window.adsbygoogle || []).push({});

a) What is the minimum force F, parallel to the plane that will prevent the block from slipping down the plane?

b) What is the minimum force F that will start the blocking moving up the plane?

c) What force F is required to move the block up the plane at constant velocity?

a) I am confused about the difference between quesiton a and b? I don't know how to determine the minimum force that will prevent the block from slipping down the plane.

b) my equations

x-direction: Fapplied - Ffriction - mgsin theta = 0

y-direction: N - mgcos theta = 0

Ffriction = usN

Ff = us (mg cos theta)

Fapplied = us (mg cos theta) + mgsin theta

Fapplied = 18.79 + 27.36 = 46.15 N

N = mgcos theta

c)

Ffriction = ukN

Ff = uk (mgcos theta)

Fapplied = uk(mg cos theta) + mg sin theta

Fapplied = 10.4 + 27.36 = 37.76N

Please correct me if i made any mistakes

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Grade 12 Physics - mass on an inclined plane (different question)

**Physics Forums | Science Articles, Homework Help, Discussion**