Calculating Power of a Light Bulb

AI Thread Summary
A 100-watt light bulb uses 360,000 Joules of energy per hour. To find the speed a 70-kg person would need to run to match this energy as kinetic energy, the formula for kinetic energy (KE = 1/2 mv^2) is applied. The calculation shows that the kinetic energy equates to 5142.86 m^2/s^2. The discussion emphasizes the importance of including the factor of 1/2 in the kinetic energy equation. The participant expresses confidence in resolving the problem after receiving clarification on the calculations.
Jim4592
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Homework Statement


How many Joules of energy does a 100 watt light bulb use per hour? How fast would a 70-kg person have to run to have that same amount of kinetic energy?


Homework Equations


How fast would a 70-kg person have to run to have the same amount of kinetic energy?


The Attempt at a Solution



1 watt = 1 J/S so... 100 J/S * 3600s = 360,000 J

360,000 kg m^2/s^2 ÷ 70 = 5142.86 m^2/s^2

my only question would be do you just square root the value and would it remove both ^2?
 
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Yes a sqrt() acts on the units as well as the number
I think you are missing a factor 2 somewhere, ke = 1/2 m v^2
 
ok thanks for your help, I'm pretty sure i can handle it from here.
 

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