A Carnot machine that operates between the temperatures TH = 250C and TL = 20C delivers one work on W = 100 J per cycle. How much heat is supplied to the system from the reservoir with hay temperature for each cycle? A: 44 J B: 109 J C: 144 J D: 227 J

The sun emits the most radiant energy at a wavelength of 504 nm. At what wavelength will one star that is 1000C warmer than the sun emit the most radiant energy? A: 265 nm B: 429 nm C: 604 nm D: 933 nm

A box is on the loading platform of a truck. The static friction number between the box and the plane is 0.45. How much acceleration can the truck have without the box starting to slip? A: 4.41 m / s2 B: 5.41 m / s2 C: 6.41 m / s2 D: 7.41 m / s2

can somebody explain how they would calculate these questions ?

thank you!!