Answer:
[tex]W = -1960 \ \rm J[/tex]
Explanation:
Given data:
Mass of the bar, [tex]m = 100 \ kg[/tex]
Height, [tex]h = 2.0 \ m[/tex]
The work done by the weightlifter can be expressed as,
[tex]W = F.h\textrm{cos} \theta[/tex]
Here,
F = mg
[tex]\theta[/tex] = angle between the fore and the vertical displacement which [tex]180^{\circ}.[/tex]
Thus,
[tex]W = 100 \times 9.80 \times 2.0\textrm{cos} 180^{\circ}[/tex]
[tex]W = -1960 \ \rm J.[/tex]
