Question

A weightlifter goes to lift a 100 kg bar over her head which is 2.0 m in the air. How much work did the weightlifter do to lift the bar?​

Answer 1

`W = -1960 \ \rm J`

Step-by-step explanation:

Given data:

Mass of the bar,
`m = 100 \ kg`

Height,
`h = 2.0 \ m`

The work done by the weightlifter can be expressed as,

`W = F.h\textrm{cos} \theta`

Here,

F = mg

`\theta` = angle between the fore and the vertical displacement which
`180^(\circ).`

Thus,

`W = 100 * 9.80 * 2.0\textrm{cos} 180^(\circ)`

`W = -1960 \ \rm J.`