A 500 kg block is pushed 300 m up a vertical wall with const

A 5.00 kg block is pushed 3.00 m up a vertical wall with constant speed by a constant force of magnitude f applied at an angle of theta = 30 degree with the horizontal. as shown in the figure right. If the coefficient of kinetic friction between block and wall is 0.30. determine the work done by F the work done by the force of gravity the work done by the normal force between block and wall By how much does the gravitational potential energy increase during the block\'s motion?

Solution

a) First, let\'s find the magnitude of F. Since the speed is constant, the sum of forces is zero

m*g-F*cos(30)*.3=F*sin(30)

solve for F
F=(5*9.8)/(sin(30)+cos(30)*.3)
F=64.5 N

The work done by the force is
F*sin(30)*4+F8cos(30)*.3*4
=196 J

b) Work done by gravity is - mg*4 = -196 J

c) Normal force N is just F cos 30°; W = N r cos , where = 90°; thus, W = N r cos 90° = 0 J, since cos 90° = 0.

d) U = mgh = 5 × 9.8 × 4 = 196 J. This is the same as the work done against gravity