When 100 J are put into a device that puts out 40 J, the efficiency of the device is A. 40%. B. 50%. C. 60%. D. 140%.
1 answer:
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The force required is 319 N
Explanation:
The force of static friction is a force that acts an object on a surface, when this object is pushed by another force to put it in motion. The direction of the force of friction is opposite to the direction of the force of push, and its value increases as the force of push increases, up to a maximum value given by:
where
is the coefficient of friction
W is the weight of the object
Therefore, in order to put the object in motion, the force applied must be greater than this value.
For the pile of leaves in this problem, we have:
(coefficient of friction)
(weight of the leaves)
Substituting, we find:
Learn more about force of friction:
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