Physics, 05.04.2021 23:30, jamesvazquez3135

A laser beam is used to levitate a metal disk against the force of Earth's gravity. (a) Derive an equation giving the required intensity of light, I, in terms of the mass m of the disk, the gravitational acceleration g, the speed of light c, and the cross-sectional area of the disk A. Assume the disk is perfectly reflecting and the beam is directed perpendicular to the disk. (Do not substitute numerical values; use variables only.)
I=
(b) If the disk has mass 3.89 g and radius 2.40 cm, find the necessary light intensity.
(c) Give two reasons why using light pressure as propulsion near Earth's surface is impractical.

Answers: 3

Show answers

Other questions on the subject: Physics

Physics, 22.06.2019 04:30, awh1088

In a system, when potential energy decreases, then entropy also decreases. true false

Answers: 2

continue

Physics, 22.06.2019 12:00, Sariyahhall1

Infrared radiation has wavelengths that are shorter than visible light is part of the visible light spectrum has wavelengths that are longer than visible light has the same wavelengths as ultraviolet radiation

Answers: 1

continue

Physics, 22.06.2019 12:00, ameliaxbowen7

Suppose a comet has an orbital period of 309.1 years around the sun. what is it’s average distance from the sun?

Answers: 1

continue

Physics, 22.06.2019 15:20, alissalhenry

Arigid tank is divided into two equal parts by a partition. one part of the tank contains 3 kg of compressed liquid water at 400 kpa and 60°c while the other part is evacuated. the partition is now removed, and the water expands to fill the entire tank. determine the entropy change of water during this process, if the final pressure in the tank is 40 kpa. use steam tables.

Answers: 3

continue

Do you know the correct answer?

A laser beam is used to levitate a metal disk against the force of Earth's gravity. (a) Derive an e...