Answer:
Power input is 125 W.
Explanation:
Given:
Force applied for lifting the barbell, [tex]F=100\textrm{ N}[/tex]
Displacement caused by the force, [tex]S=2.5\textrm{ m}[/tex]
Time taken for the lift,[tex]t=2\textrm{ s}[/tex]
Work done by the weightlifter in raising the barbell is given as,
[tex]Work=Force\times displacement\\Work=100\times 2.5\\Work=250\textrm{ J}[/tex]
Now, power input is given as,
[tex]Power=\frac{Work}{Time}\\\\Power=\frac{250}{2}=125\textrm{ W}[/tex]
Therefore, the power input is 125 watts.
