The power of the weightlifter is equal to the ratio between the work done by it and the time taken:
[tex]P= \frac{W}{t} [/tex]
since we know the power and the time, we can find the work done:
[tex]W=Pt=(294 W)(10 s)=2940 J[/tex]
For the work-energy theorem, this work done by the lifter is equal to the gravitational potential energy gained by the mass, which is given by:
[tex]U=mg \Delta h[/tex]
where m is the mass and [tex]\Delta h[/tex] is the increase in height. Rearranging the formula and using W=U, we can find the mass:
[tex]m= \frac{U}{g\Delta h}= \frac{2940 J}{(9.81 m/s^2)(2 m)}=149.8 kg [/tex]
