Answer:
The power in watts is 66.15 Watts
Explanation:
In this problem, we will use the concept of the work-energy theorem to relate the potential energy of the boy and compute his power in running over the stairs.
Formula to use
a. PE = mgh
b. P = W/t
where
PE is the potential energy, the unit is in Joules (J)
m is the mass, the unit is in kg
g is the pull of the Earth's gravity, 9.8 m/s²
h is the height, the unit is in meter (m)
P is the power, the unit is in J/s or Watts
W is the work, the unit is in Joules (J)
t is the time, the unit is in seconds
Given information
m = 45 kg
h = 25 x 30 cm = 750 cm = 7.5 m
t = 5.0 s
P = ?
Solving the problem
Let us solve the potential energy of the boy
PE = mgh
PE = (45 kg)(9.8 m/s²)(7.5 m)
PE = 3307.5 J
Now, this energy is also equivalent to work according to the concept of energy-work theorem, therefore, PE = Work, so Work = 3307.5 JJ.
Now, let us solve the power exerted by the boy by running over the stairs using
P = W/t
Substitute the given data
P = 3307.5 J / 50 s
P = 66.15 Watts
Therefore, the power exerted by the boy is 66.15 Watts.
To learn more, just click the following links:
https://brainly.ph/question/1429339
- Relationship of work and energy
https://brainly.ph/question/411277
#LetsStudy
