Acceleration=velocity/time
acceleration=28/4.22
therefore, acceleration=6.64
Answer:
(a) 
(b) P = 0.816 Watt
Explanation:
(a)
The power radiated from a black body is given by Stefan Boltzman Law:

where,
P = Energy Radiated per Second = ?
σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴
T = Absolute Temperature
So the ratio of power at 250 K to the power at 2000 K is given as:

(b)
Now, for 90% radiator blackbody at 2000 K:

<u>P = 0.816 Watt</u>
given that
mass of ball = 0.095 kg
initial velocity of ball towards the wall = 40 m/s
final velocity of the ball after it rebound = 30 m/s
now change in momentum is given as



So change in momentum will be 6.65 kg m/s
Answer:
Electromagnetic waves do not require a medium in order to transport their energy. Mechanical waves are waves that require a medium in order to transport their energy from one location to another. ... Sound is a mechanical wave and cannot travel through a vacuum.