Suppose that you designed a spacecraft to work by photon pressure. The sail was a completely absorbing fabric of area 1.0 km^2 and you directed a red laser beam of wavelength 650 nm on it from a base on the moon. What is the (a) force, (b) pressure exerted by the radiation on the sail? (c) suppose the mass of the spacecraft is 1 kg. Given that after a period of acceleration from standstill, speed = (force/mass) x time, how long would it take for the craft to accelerate to a speed of 1 m/s