A spherical satellite of diameter D is in orbit about the earth and is coated with a diffuse material for which the spectral absorptivity is 0.6 for 3 m and 0.3 for 3 m. When it is on the dark side of the earth, the satellite sees irradiation from the earths surface only. The irradiation may be assumed to be incident as parallel rays, and its magnitude is GE 340 W/m2 . On the bright side of the earth the satellite sees the earth irradiation GE plus the solar irradiation GS 1368 W/m2 . The spectral distribution of radiation from the earth may be approximated as that of a blackbody at 280 K, and the temperature of the satellite may be assumed to remain below 500 K. What is the steady-state temperature of the satellite when it is on the dark side of the earth and when it is on the bright side? 12.131
PY 205 Week 3 Notes Chapter 4 and 5 Newton’s Laws 1. Velocities don’t change unless a net force acts upon it (qualitative) 2. The acceleration of a body is directly proportional to the net force acted on it (quantitative) a. Fnet = (mass)(acceleration) 3. Forces occur between two objects – if A exerts a force on B then B exerts a negative force on A. a. Fnet = Fxi +Fyj + Fzk b. The sum of all the forces on x = ma(x) c. The sum of all the force on y = ma(y) Applications of Newton’s laws - Kinetic motion - sliding friction - The force acts opposite to the direction of the object’s velocity - Normal force = shows that the friction force is approximately proportional to the normal force – the
