A loaded penguin sled weighing 80 N rests on a plane inclined at 20° to the horizontal. .??>>>>....?

Question

A loaded penguin sled weighing 80 N rests on a plane inclined at 20° to the horizontal. Between the sled and the plane the coefficient of static friction is 0.24, and the coefficient of kinetic friction is 0.14.

(a) What is the minimum magnitude of the force F, parallel to the plane, that will prevent the sled from slipping down the plane?
wrong check mark N

(b) What is the minimum magnitude F that will start the sled moving up the plane?
N

(c) What value of F is required to move the block up the plane at constant velocity?
N

Answer 1

a) A FBD of the sled at rest yields force parallel to the incline as
F+80*cos(20)*0.24-80*sin(20)=0
solve for F
F=9.32

b)
F-80*cos(20)*.24-80*sin(20)=0
solve for F
F=45.4

c)
F-80*cos(20)*.14-80*sin(20)=0
solve for F
F=37.9

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Answer 2

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