 #1
 49
 1
Homework Statement
 4.18
With reference to Example 4.21, consider the design of a solar sail
intended to reach escape velocity from the Earth 2gRe = 11.2 km/s using only the pressure due to sunlight. The sail is made of a Kapton⃝R film 0.0025 cm thick with a density 1.4 g/cm3. Take the solar constant to be 1370 watts/m2, assumed to be constant during the acceleration.
(a) What is the acceleration near the Earth due to sunlight pres sure alone?
(b) How far from the Earth, as measured in units of the Earth’s radius, Re, would the sail have to be launched so that it could es cape from the Earth?
Homework Equations
attached
The Attempt at a Solution
Solution attached
no issues with part a
part b: I am getting the wrong answer as solution come up with r ≥ 194*R_{E}
Help is greatly appreciated as solutions suggest a due to sun photon influx in towards the sun as my understanding should be away!
Attachments

36.3 KB Views: 124