Calculating Mass Increase of Earth Annually From Sunlight

[a.a]

Homework Statement

By how much does the mass of the Earth increase each year as a result of sunlight reaching it? Radiation from the sun reaches the EArth at a rate of 1400W/m^2 of area perpendicular to the energy flow. Assume 100% absorption.

Homework Equations

I'm sorry but I haven't the slightest clue as to how to approach this question.
But we are given the Radius of the Earth as 6.36 * 10 ^6 m

The Attempt at a Solution

The answer is sopposed to be 1.23 * 10^8

 

[malawi_glenn]

I'll give you a hint: What is the area that is seen by the rays coming from the sun?

 

[a.a]

First to answer your question: only half the surface area? Which would be 2pi r^2

So we have to solve for power useing power = rate * surface area

then solve for energy useing energy = power * time

then E = mc^2 to solve for mass..

Would this mass be the increase or the mass after one year?

 

[Dick]

Cross sectional area. Not 1/2 of surface area. Cross section, i.e. pi*r^2. And yes, you seem to know how to calculate the rate of energy absorption and solve for the equivalent mass.