Calculating Power of a Light Bulb

[Jim4592]

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?

 

[mgb_phys]

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

 

[Jim4592]

ok thanks for your help, I'm pretty sure i can handle it from here.