Answer
See answers.
Work Step by Step
a. We assume that the suit is perfectly reflecting, so use equation 22–10b to calculate the radiation pressure of $2\overline{I}/c$. The force is the pressure multiplied by the area.
$$F_{laser}=PA=\frac{2\overline{I}}{c}A=\frac{2 (3.0W/A)}{c}A$$
$$=\frac{2(3.0W)}{3.00\times10^8m/s}=2.0\times10^{-8}N$$
b. Use Newton’s law of universal gravitation, equation 6–1, to estimate the gravitational force.
$$F_g=G\frac{m_{shuttle}m_{astronaut}}{r^2}$$
$$=(6.67\times10^{-11}N\cdot m^2/kg^2)\frac{(103000kg)(120kg)}{(30m)^2}\approx9.2\times10^{-7}N$$
c. The gravitational force is larger, by a factor of about 46.
