Pablo prepares to lift a barbell. during which stage of the lift does pablo do work on the barbell?

when he holds the barbell up above his head
when he applies force to the barbell but has not moved it
when he lifts the barbell from the floor to his chest
when he lets go of the barbell and allows it fall to the ground

Option (c) is the correct answer.

Explanation:

Force is defined as work divided by displacement.

Mathematically,       F =

where                w = work

                          d = displacement

Therefore, when Pablo lifts the barbell from the floor to his chest then work on the barbell is done as it has displaced from ground to the chest.

Thus, we can conclude that out of the given options, when he lifts the barbell from the floor to his chest at this stage of the lift Pablo do work on the barbell.

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table