Power(p) = 2kW
Time(t)= 3 h
Work done(w) = ?
p = w / t
w = p × t
w = 2kW × 3 h
w = 6kWh
Converting 6kWh to Joules,
6kWh
6×(10^3)h ( k = 10^3 )
6×10^3×(60×60) ( 1 hour = 60 × 60 sec)
2.2×10^7 J in 2 significant figures
Answer:
The average power delivered by the elevator motor during this period is 6.686 kW.
Explanation:
Given;
mass of the elevator, m = 636 kg
initial speed of the elevator, u = 0
time of motion, t = 4.5 s
final speed of the elevator, v = 2.05 m/s
The upward force of the elevator is calculated as;
F = m(a + g)
where;
m is mass of the elevator
a is the constant acceleration of the elevator
g is acceleration due to gravity = 9.8 m/s²

F = (636)(0.456 + 9.8)
F = (636)(10.256)
F = 6522.816 N
The average power delivered by the elevator is calculated as;

Therefore, the average power delivered by the elevator motor during this period is 6.686 kW.
Krypton ... symbol Kr ... is an element. It's element number 36, because
there are 36 protons in the nucleus of every atom of Krypton.
Krypton has nothing to do with Superman, except that about 75 years ago,
the creators of Superman thought it was a cool-sounding scientific word,
so they chose it for the name of his home planet.