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a. The work done by the hiker against gravity.
b. The average power output in watts and horsepower.
c. The rate of energy input required.
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Answer to Problem 89GP
Solution:
a. The work done by the hiker against gravity is
b. The average power output in watts and horsepower are 54 watts and
c. The input power is 360 watts and
Explanation of Solution
Given:
The mass of the hiker is
Total height covered by the hiker:
Time taken by the hiker to climb to the given height is:
Formula used
The formula for work done against gravity is
Where, m is the mass, g is the gravitational acceleration and h is the height.
The formula for power is
Where, W is the work done and t is the time.
Calculations
Part a
The work done by the hiker against gravity is:
Part b
The average power in watts:
In horsepower:
Part c
Since the efficiency is 15%, therefore the output is this much percent of input.
We have
Therefore, to calculate
Conclusion:
a. The work done by the hiker against gravity is
b. The average power output in watts and horsepower are 54 watts and
c. The input power is 360 watts and
Chapter 6 Solutions
Physics: Principles with Applications
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