The Earth has a mass of 5.98*1024 kg. A 100 kg satellite is set up in stable orbit 1.024*107 m above the center of the planet. The satellite is currently experiencing a force of gravity of 380 N . What is the mass of the satellite?
How fast is the satellite moving?
What would happen to the satellite if it increased its orbital velocity, but still remained in a stable orbit?

Athin electrical heater is inserted between a long circular rod and a concentric tube with inner and outer radii of 20 and 40 mm. the rod (a) has a thermal conductivity of ka = 0.15 w/(m*k), while the tube (b) has a thermal conductivity of kb = 0.8 w/(m*k) and its outer surface is subjected to convection with a fluid of temperature t= -15°c and heat transfer coefficient 60 w/(m2 *k). the thermal contact resistance between the cylinder surfaces and the heater is negligible. (a) determine the electrical power per unit length of the cylinders (w/m) that is required to maintain the outer surface of cylinder b at 15°c. (b) what is the temperature at the center of cylinder a?