Question

It takes some work for you to lift an object 20cm. How much work must you do to lift the same object 40cm?

Answer 1

Twice the work needed to lift the 20cm object

Step-by-step explanation:

Work done is derived using the expression below;

Work done = Force x distance

For this problem, we are lifting through a vertical height;

Work done = mg x h

mg is the weight of the body;

Since both bodies have the same weigh;

W1 is the workdone to lift 20cm

W2 is the workdone to lift 40cm

For the first lift;

W1 = (mg) x 20cm

(mg) =
`(W1)/(20)`

For the second lift;

W2 = (mg) x 40cm

Since they both have the same weight

(mg) =
`(W2)/(40)`

Equating the two weights;

`(W1)/(20)` =
`(W2)/(40)`

20W2 = 40W1

W2 =
`(40W1)/(20)` = 2W1