Math Problem Statement

A 65 kg human sprinter can accelerate from rest to 10 m/s in 2.9 s . During the same time interval, a 26 kg greyhound can go from rest to 20 m/s. What is the average power output of the human?

Solution

To calculate the average power output of the human, we’ll go through a few steps involving energy and time.

Step 1: Find the Work Done (Change in Kinetic Energy)

The work done by the human is equal to the change in kinetic energy, which we can calculate using: Work=ΔKE=12mv2\text{Work} = \Delta KE = \frac{1}{2} m v^2 where:

  • m=65kgm = 65 \, \text{kg} (mass of the human)
  • v=10m/sv = 10 \, \text{m/s} (final velocity)

So, Work=12×65×(10)2=12×65×100=3250J\text{Work} = \frac{1}{2} \times 65 \times (10)^2 = \frac{1}{2} \times 65 \times 100 = 3250 \, \text{J}

Step 2: Calculate the Average Power

Power is the work done per unit of time. Given the time t=2.9st = 2.9 \, \text{s}: Power=Workt=32502.91120.69W\text{Power} = \frac{\text{Work}}{t} = \frac{3250}{2.9} \approx 1120.69 \, \text{W}

Answer

The average power output of the human is approximately 1120.69 watts (W).

Would you like a breakdown of each calculation step, or do you have any questions?


Here are some related questions you might find helpful:

  1. What would be the power output if the sprinter increased speed to 12 m/s in the same time?
  2. How does the power output of the human compare to that of the greyhound?
  3. If the sprinter took 3.5 seconds instead of 2.9 seconds, what would the average power output be?
  4. What is the relationship between power, work, and time in physics?
  5. How does mass affect the power output in cases of similar acceleration?

Tip: Remember, power measures how quickly work is done over time, not just the total amount of energy expended.

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Math Problem Analysis

Mathematical Concepts

Kinetic Energy
Work-Energy Principle
Power
Time

Formulas

Work = 1/2 * m * v^2
Power = Work / time

Theorems

Work-Energy Theorem
Power Formula

Suitable Grade Level

Grades 9-12