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As shown in the figure below, a box of mass m = 67.0 kg (initially at rest) is p

ID: 1592831 • Letter: A

Question

As shown in the figure below, a box of mass m = 67.0 kg (initially at rest) is pushed a distance d = 85.0 m across a frictionless warehouse floor under the influence of two forces. A force of F_1 = 213 N directed at an angle of 30.0degree below the horizontal and a force F_2 = 110 N acting in a direction that opposes the motion. Determine the following. work done on the box by the force F_1 work done on the box by the force F_2 work done on the box by the force of gravity F_g work done on the box by the normal force N net work done on the box by finding the sum of all the work done on the box by the individual forces net work done on the box by finding the net force acting on the box and then finding the work done by this net force

Explanation / Answer

a) Work done = F.d = F d cos@

work done by force F1 = F1 d cos30

W = 213 x 85 x cos30 = 15679.39 J


b) work done by F2 = F2 d cos180

= 110 x 85 x cos180 = - 9350 J


c) Work done by gravity = mg d cos90 = 0

d) work done by normal = N d cos90 = 0


e) Net work = 15679.39 - 9350 = 6329.39 J

f)Net force = (F1cos30 - F2)i + F1sin30j

= 74.46i + 106.5j


d = 85 i


W = F.d = ( 74.46i + 106.5j ) . ( 85 i )


= 74.46 x 85 = 6329.1 J