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<h3>Explanation</h3>
The Stefan-Boltzmann Law gives the energy radiation <em>per unit area</em> of a black body:
where,
the total power emitted, 
the surface area of the body, 
the Stefan-Boltzmann Constant, and
the temperature of the body in degrees Kelvins.
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Keep as many significant figures in as possible. The error will be large when is raised to the power of four. Also, the real value will be much smaller than 
since the emittance of a human body is much smaller than assumed.
Wave speed = frequency * wavelength
Input the numbers into this equation :
Wave speed = 200 * 3
Work it out and you will get the answer :
Wave speed = 600 m/s
Answer:
never lol
studying is your work
but why all are doing I don't know=_=
A) 
The total energy of the system is equal to the maximum elastic potential energy, that is achieved when the displacement is equal to the amplitude (x=A):
(1)
where k is the spring constant.
The total energy, which is conserved, at any other point of the motion is the sum of elastic potential energy and kinetic energy:
(2)
where x is the displacement, m the mass, and v the speed.
We want to know the displacement x at which the elastic potential energy is 1/3 of the kinetic energy:
Using (2) we can rewrite this as
And using (1), we find
Substituting 
into the last equation, we find the value of x:
B) 
In this case, the kinetic energy is 1/10 of the total energy:
Since we have
we can write
And so we find:
Answer:
A
Explanation:
The equation of power is defined as Power = Workdone/Time Taken
And workdone = Force x Distance so using these equations we get they workdone is, 200x 10 = 2000Nm.
Dividing workdone with time will yield power, 2000 ÷ 8 = 250 Nm/s = 250W.
