Explanation:
A student weighing (W) = 700 N,
The constant speed to the top of vertical rope (ΔV) = 8 m and
Time (T) = 10 s
To find, the average power expended by the student to overcome gravity (most nearly) = ?
We know that,
Power = [tex]\dfrac{Work}{Time}[/tex]
= [tex]\dfrac{(Weight)(Vertical rise)}{Time}[/tex]
= [tex]\dfrac{W\delta V}{T}[/tex]
= [tex]\dfrac{700N(8m)}{10s}[/tex]
= 70 × 8 W
= 560 W
∴ The average power expended by the student to overcome gravity (most nearly) = 560 W
Thus, the required "option c) 560 W" is correct.
