Special Relativity Energy Problem a little confused!

  • #1
Engineergirl2
7
0

Homework Statement


At Earth's location, the intensity of sunlight is 1.5kW/m^2. if no energy escaped earth, by how much would Earth's mass increase in 1 day?


Homework Equations


ΔE=Δmc^2+ΔKE
Rearth=6.378x10^3


The Attempt at a Solution


I know that the change in kinetic energy does not change, so that value can go to 0. But I'm not sure what exactly I'm supposed to start with. The answer is supposed to be 1.83x10^5kg/day. Any help would REALLY be appreciated.
 

Answers and Replies

  • #2
nasu
3,957
582
You need to calculate how much energy is received in 1 day by the entire Earth.
You know how much is received in one second (kW is energy per second) by 1 m^2 of the surface.
 
  • #3
Engineergirl2
7
0
Do I use cross sectional area?
 
  • #4
nasu
3,957
582
You can use the cross sectional area and assume the radiation is normal on it.
Integrating over the area of the (hemi-)sphere and taking into account the angle of incidence for each location will produce the same result.
 

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