<h2>
Answer: 0.17</h2>
Explanation:
The Stefan-Boltzmann law establishes that a black body (an ideal body that absorbs or emits all the radiation that incides on it) "emits thermal radiation with a total hemispheric emissive power proportional to the fourth power of its temperature":
(1)
Where:
is the energy radiated by a blackbody radiator per second, per unit area (in Watts). Knowing 
is the Stefan-Boltzmann's constant.
is the Surface area of the body
is the effective temperature of the body (its surface absolute temperature) in Kelvin.
However, there is no ideal black body (ideal radiator) although the radiation of stars like our Sun is quite close. So, in the case of this body, we will use the Stefan-Boltzmann law for real radiator bodies:
(2)
Where 
is the body's emissivity
(the value we want to find)
Isolating from (2):
(3)
Solving:
(4)
Finally:
(5) This is the body's emissivity
Answer:
3875J
Explanation:
Energy is defined as the power × time
And it's defined as
Power = IV - I- current and V- voltage
Now quantity of electricity; Q = I × t
Where I is current and t is time
Now Energy = I ×V×t = V× I×t = V× Q;
where Q is quantity of electricity 775C and V is 5.0volt
Hence 775 × (5) =3875J
1) If the object changes directions with the same speed, it will be changing its velocity, because velocity is a vector, which depends on both magnitude and direction. Speed is just magnitude regardless of direction.
2) Rotational motion.
