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Grade 11Mechanics

A horizontal force F of 12 lb pushes a block weighing 5.0 lb against a vertical wall (Fig.) The coefficient of static friction between the wall and the block is 0.60 and the coefficient of kinetic friction is 0.40. Assume the block is not moving initially. (a) Will the block start moving? (b) What is the force exerted on the block by the wall?
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

Profile image of Simran Bhatia
11 Years agoGrade 11
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1 Answer

Profile image of Aditi Chauhan
11 Years ago
236-2076_1.PNG
The weight of the block is 5.0 lb, and is smaller than static force of friction in magnitude. Therefore, the frictional force will manage to keep the block in position.
(b)
It is important to note that the magnitude of frictional force fs that can hold the block in position is equal to its weight. 236-1666_1.PNG
Therefore, the magnitude of net force acting on the block is 13 lb .