Please can someone help me with this problem?

Question

A worker transports bricks from a pile to the endgate of a pick-up truck, and then pushes the bricks to the front of the truck’s bed.

Is work being done in each of the steps, and if so, please explain (I know work is being done, but I don't know how to explain it other than saying the worker did work)

Answer 1

work done= Force * distance moved in direction of force .

When the work pick up the pile of brick from the ground work is done against gravity as distance have been moved in the direction of force . when he moves to the end gate of pick up truck no work done since all forces are vertical and distance he is moving is not in the direction of forces , now when pushes the bricks to the front bed he applies a force which is then moved in the direction of force so work again has been done .


Dont confuse your self with energy and work done ..

Answer 2

One fella used to say: "There is work and there is work."

Let's do it step by step
Work equal effort times the distance along which the force was applied.

1, "A worker transports bricks from a pile to the endgate"
a) the forker lifts a brick (or a few bricks) a certain height h
Work =W1= mgh1
b) He moves the bricks, first by accelerating wit acceleration a1 and then negatively accelerating a2 before the 'endgate'
W2= F1S1 + F2S2= m(a1S1 + a2S2)
Notice there is no change in sign since work is a scalar quantity
c) it lowers the brick down by h2
W3=mgh2
d) he pushes the bricks onto the bed a certain distance S.
W4=(force of accelerating bricks of mass m + force of friction between the bricks and trucks bed)
W4= (ma+umg)S



Please note that in step 2 as the worker moves the bricks horizontally without acceleration the worker uses energy but does no work on the bricks.

I hope that helps
Have fun!

Answer 3

The worker has to use energy to lift the bricks from the pile and carries them over to the pick-up truck. As the bricks fall onto the bed, they exert a small force upon the bed of the truck as well. This continues until all the bricks are loaded. When the worker has to push the bricks, he exerts energy onto the bricks, and the bricks onto the truck--static friction occurs until the energy the worker exerts is greater than that of the friction between the bricks and the bed, creating sliding friction from the time to push the bricks from one end to the other.