- #1
tempneff
- 85
- 3
Homework Statement
A motionless spacecraft powered by a “solar sail” at a distance of 1.20 AU
from the sun has a perfectly reflective sheet of lightweight material that allows the spacecraft to accelerate by using the radiation pressure from the sun. If a certain sail is in the shape of a square of side 800 m, its velocity is 38.5 km/s when it reached a distance of 3.50 AU from the sun. The Force at 1.2 AU is 4.18 N and at 3.54 AU is 0.492.
Answer range: 3.0 to 3.4 years
Homework Equations
[tex]a= \frac{v_f^2-v_0^2}{2(x_f-x_0}[/tex]
[tex]t=\frac{v_f-v_0}{a}[/tex]
[tex]1 AU \approx 1.5\times 10^8 km[/tex]
[tex]1 year \approx 3.16 \times 10^7 s[/tex]
The Attempt at a Solution
I tried these kinematics equations and can't see his answer range, so I think I am missing
something.
[tex]t=\frac{2(x_f-x_0)}{v_f}=1.79\times 10^7 s\neq 3 years-ish[/tex]
I assume I can't use constant acceleration, no?