Answer: 1479 W
Explanation:
The work done by Mary is equal to its gain in gravitational potential energy, which is equal to
\(W=\Delta U=mg\Delta h\)
where
\(mg=87 N\) is Mary's weight
\(\Delta h=102 m\) is the distance
Substituting,
\(W=(mg)(d)=(87 N)(102 m)=8,874 J\)
And the power is equal to the ratio between the work done and the time taken:
\(P=\frac{W}{t}=\frac{8,874 J}{6.0 s}=1479 W=1.48 kW\)
