Question by John D: Calculations involving flux of sunlight?
I have a modern physics problem where I need to calculate total energy and momentum of photons provided to a solar sail.
I am given that there’s a spacecraft travelling from Earth to Mars, powered by a solar sail of 600 m^2 with constant flux of sunlight F = 1373 W/m^2 and this takes a time of 5 years.
Then I have to find the spacecraft’s final velocity, and then it’s kinetic energy.
I have looked in our textbook and online, and can’t find equations on how to solve this. Could anybody help me please?
Best answer:
Answer by Magical P
This seems to be a kinematic based problem.
if F = 1373 W/m^2 = ma
where m is the mass of the spaceship and a is the acceleration of the ship.
we know the the area of the sail is 600 m^2, and its receiving the solar power…
remember flux is defined as a flow of something through a specific area.
Lets take F = 1373 and multiply by the area of the sale..we get:
F = 1373 W/m^2 * 600 m^2 = 823800 W = ma
from kinematics we know that:
V = Vo + at
where V is the final velocity, Vo is the initial velocity (this is zero since we started at a speed of zero), and t is in kg over W.
This is where i lose you, since i have no idea what W stands for..
but kinetic energy = .5 * m * v^2
Hope that sorta helped!
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