Aspherical pot of coffee contains 0.50 l of liquid at an initial temperature of 80°c. the pot has an emissivity of 0.40, and the surroundings are at a temperature of 20°c. calculate the coffee’s rate of heat loss by radiation. use σ = 5.67 × 10–8 w/(m2 • k4).
a.
6.1 w
b.
4.9 w
c.
3.0 w
d.
5.6 w

Imagine you are riding on a yacht in the ocean and traveling at 20 mph. you then hit a golf ball at 100 mph from the deck of the yacht. you see the ball move away from you at 100mph, while a person standing on a near by beach would observe your golf ball traveling at 120 mph (20 mph + 100 mph). now imagine you are aboard the hermes spacecraft traveling at 0.1c (1/10 the speed of light) past mars and shine a laser from the front of the ship. you would see the light traveling at c (the speed of light) away from your ship. according to einstein’s special relativity, how fast will a person on mars observe the light to be traveling? a) 0.1c (1/10 the speed of light) b) c (the speed of light) c)1.1c (c+0.1c)