Question

A) You have just moved into a new apartment and are trying to arrange your bedroom. You would like to move your dresser of weight 3,500 N across the carpet to a spot 5 m away on the opposite wall. Hoping to just slide your dresser easily across the floor, you do not empty your clothes out of the drawers before trying to move it. You push with all your might but cannot move the dresser before becoming completely exhausted. How much work do you do on the dresser?
W> 1.75 x 10^4 J
W = 1.75 x 10^4 J
1.75 x 10^4 J > W > 0 J
W = 0 J

B) A box of mass m is sliding down a frictionless plane that is inclined at an angle ϕ above the horizontal, as shown in the figure (Figure 2) . What is the work done on the box by the force due to gravity w, if the box moves a distance d?

Answer 1

Answer:

A. W = 0joule

B.W = d * w * cos (90 -ø)

Explanation:

work done is force multiplied by distance since the distance covered by the dresser is zero so automatically work done in moving the dresser is 0 (zero)

B. The component of weight of box along the inclined plane = w * cos ( 90 - ø )

Where ø is the angle of inclination to the horizontal

W = weight of body due to gravity.

Since the distance traveled by box due to gravity = d

So therefore:

W = d * w * cos (90 -ø)

W = work done

N.b

See attached sketch for comprehension