Question

The physics of work on an accelerating object.

a) A sled is dragged along by a 25.0 N force that is applied at an angle of 50.0 degrees above the horizontal. The sled moves to the right and friction is negligible, so it is constantly accelerated while the force is being applied. How much work is done after the sled has moved 2.5 m?

b) Given the motion of the sled, how must the downward force of gravity on the sled compare to the vertical component of the applied force?

c) Was any work done in the vertical direction?

Answer 1

a) horizontal component of force=Fh=F*cos50=25*cos 50=16.1 N

Horizontal displacement=d=2.5 m

Work done by force=16.1*2.5=40.25 J

b) for the given motion, to ensure that displacement is horizontal, there should be no uplift of the object from the ground. For this to happen, the weight of the object should be equal to or greater than the vertical component of applied force

Therefore, weight if objcet should be minimum 25*sin50=19.2 N

c) since therr is no vertical movement of the object ,the work done by vertical force is zero