Question

Two girls are estimating each other's power. One runs up some step
ng each other's power. One runs up some steps, and the other times her. Here are their
results:
height of one step = 20 cm
number of steps = 36
mass of runner = 45 kg
time taken = 4.2 s
a .Calculate the runner's weight. (Acceleration due to gravity g=10m
b .Calculate the increase in the girl's gravitational potential energy as she runs up the steps.
c. Calculate her power. Give your answer in kilowatts (kW).​

Answer 1

Answer:

Explanation:

a)Runner's Weight = mg = 450 N

b) height of one step = 20 cm

number of steps = 36

total ascend = 720 cm  = 72 m

increase in the girl's gravitational potential energy = work done by girl against gravity = mgh = 32400 J

c) power = work / time =32400/4.2=7714.2W = 7.7KW