Find the power of a man running (work and potential energy)

• Jujubee37
In summary, the conversation discusses different approaches to solving a problem involving finding work and distance using the work energy theorem. One person suggests using the equation W=Fd, while another suggests using the equation W=1/2mv^2. The conversation also touches on the importance of correctly calculating distance and the possibility of a misreading in the problem.
Jujubee37
Homework Statement
A man that weighs 10 kg starts at rest and takes 5 seconds to achieve a a speed of 3 m/s. how much power did the man produce?
Relevant Equations
W=(f)(d)
p=w/t
I started of by trying to find the work for I got stuck because I did not know how to solve for the Force. I solved for the distance by doing 3=d/5s which gave me 15m. but then I couldn't figure out where to go next in the problem because I don't know how to solve for (f) so an explanation would be greatly appreciated thanks.

Use the work energy theorem, the total work will be equal to the final kinetic energy.

rsk
Delta2 said:
Use the work energy theorem, the total work will be equal to the final kinetic energy.
would that be FD=1/2mv^2 ?

i suppose by FD you mean the work W=Fd? then yes.

10 kg is a very small man, weighs or not.

Jujubee37
Delta2 said:
i suppose by FD you mean the work W=Fd? then yes.
Okay thank you I got it I think. 9 W

Your original approach will also work, ie by looking for the force (find the acceleration first) BUT only if you calculate the dstance correctly - what you've done there assumes that he was running at 3 ms⁻1 for the whole time.

Jujubee37
Jujubee37 said:
Okay thank you I got it I think. 9 W
Yes, but finding distance and work is more than a little roundabout. Was "work" specified in the problem ?

Last edited:
rsk said:
10 kg is a very small man, weighs or not.

1. What is the relationship between work and potential energy in a man running?

The work done by a man running is converted into potential energy, which is stored in his muscles. This potential energy can then be used for further movement or other tasks.

2. How is the power of a man running calculated?

The power of a man running can be calculated by dividing the work done by the time taken. It is represented by the formula P = W/t, where P is power, W is work, and t is time.

3. Does the speed of a man running affect his power?

Yes, the speed of a man running does affect his power. The faster he runs, the more work he is doing in a shorter amount of time, resulting in a higher power output.

4. How does the terrain affect the power of a man running?

The terrain can greatly affect the power of a man running. Running on a flat and smooth surface requires less work and therefore results in a lower power output compared to running on rough or uphill terrain.

5. Can the power of a man running be increased?

Yes, the power of a man running can be increased through training and improving his strength, speed, and endurance. Proper nutrition and rest also play a crucial role in increasing power output.

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