Answer: mass x height x gravitational field strength (g)
note: gravitational field strength (g) = 10 N/Kg
55 x 15 x 10 = 8250
gpe = 8250j
Explanation:
Answer:
(a) 2800 J
(b) 31.28 %
Explanation:
Heat intake, Q1 = 8950 J
Heat discard, Q2 = 6150 J
(a) Work = intake heat energy - discarded heat energy
W = Q1 - Q2 = 8950 - 6150 = 2800 J
(b) Efficiency = 1 - Q2 / Q1
Efficiency = 1 - (6150 / 8950) = 0.3128 = 31.28%
Well we can't see the picture that the teacher has, and we have to figure out what's in the picture from some clues in the answer choices. The picture seems to show an atom with 3 protons and 3 neutrons in the nucleus, and 3 electrons whizzing around the nucleus.
If that's what's in the picture, then Mike is correct (first choice), because the atomic number shows the number of protons in all atoms. There are 3 protons and the atomic number of lithium is 3.
Second choice . . . False, because electrons are not involved in the atomic mass.
Third and fourth choices . . . both false; sadly, Joan is woefully unclear on the concepts.
Answer:
5.327
Explanation:
Stefan-Boltzmann law states that the total radiant heat power emitted from a surface is proportional to the fourth power of its absolute temperature.
W = σT⁴
Where,
W is the total radiant heat power emitted from a surface
σ is constant of proportionality, called the Stefan–Boltzmann constant = 5.67 × 10⁻⁸ Wm⁻²K⁻⁴
T is absolute temperature in kelvin
For the first star, T = 5200 K
∴ W₁ = σ(5200)⁴
For the second star, T = 7900 K
∴ W₂ = σ(7900)⁴
The amount of energy radiated by the hotter star W₂, with respect to the other star W₁ is,
W₂ / W₁ = σ(7900)⁴ / σ(5200)⁴