Two astronauts, working in the zero-g vacuum of space, are testing an advanced-materials ultra-light-weight retro-reflecting structure for its potential as a solar sail. A surprisingly rigid square section of the material, with an edge length of 12.7 cm and a mass of only 498.1 mg, is completely composed of corner reflectors. These reflectors have the convenient property that an incident beam of light is reflected back towards its source even when the angle of incidence is not perpendicular. The astronauts are using a 988 W laser with a beam that has a diameter of 4.36 mm. ▷ A The two astronauts, separated by 6.49 m, are at rest in some frame of reference. The first astronaut gently releases the test square so that it is at rest. The laser is then directed at the center of the square with approximately normal incidence. How much time, in seconds, elapses before the test square crosses the distance between the two astronauts?

Two astronauts, working in the zero-g vacuum of space, are testing an advanced-materials ultra-light-weight retro-reflecting structure for its potential as a solar sail. A surprisingly rigid square section of the material, with an edge length of 12.7 cm and a mass of only 498.1 mg, is completely composed of corner reflectors. These reflectors have the convenient property that an incident beam of light is reflected back towards its source even when the angle of incidence is not perpendicular. The astronauts are using a 988 W laser with a beam that has a diameter of 4.36 mm. ▷ A The two astronauts, separated by 6.49 m, are at rest in some frame of reference. The first astronaut gently releases the test square so that it is at rest. The laser is then directed at the center of the square with approximately normal incidence. How much time, in seconds, elapses before the test square crosses the distance between the two astronauts?