Average intensity of electromagnetic wave is given by
I= (speed of light*permittivity*sq. electric field)/2
Speed of light = 3x10^8 m/s
Permittivity = 8.85x10^-12
Therefore,
Electric field = sqrt (2I/ (speed of light xpermittivity)) = sqrt ((2*4.50)/(3*10^8*8.85*10^-12)) = 58.22 V/m
Mechanical Energy transforms into Thermal due to the moving parts rubbing on eachother creating heat and friction.
Answer:
Explanation:
means initial angular velocity, which is 0 rev/min
means final angular velocity, which is 
t means time t= 3.20 s
one revolution is equivalent to 2πrad so the final angular velocity is:
= (2π/60) *2.513*10^{4} rad/s
= 2628.5 rad/s
so the angular acceleration, α will be:
α = 2628.5 rad/s / 3.20 s
so the rotational motion about a fixed axis is:
+ 2αΔTita where ΔTita is the angle in radians
so now find the ΔTita the subject of the formula
ΔTita = 
Answer:
8) 709.8875 J
9) The object is at 7.24375 m from the ground
10) Kinetic energy increases as the object falls.
Explanation:
We use the expression for the displacement h(t) as a function of time of an object experiencing free fall:
h(t) = hi - (g/2) t^2
hi being the initial position of the object (10m) above ground, g the acceleration of gravity (9.8 m/s^2), and t the time (in our case 0.75 seconds):
h(0.75) = 10 - 4/9 (0.75)^2 = 7.24375 m
This is the position of the 10 kg object after 0.75 seconds (answer for part 9)
Knowing this position we can calculate the potential energy of the object when it is at this height, using the formula:
U = m g h = 10kg * 9.8 (m/s^2) * 7.24375 m = 709.8875 J (answer for part 8)
Part 10)
the kinetic energy of the object increases as it gets closer to ground, since its velocity is increasing in magnitude because is being accelerated in its motion downwards.
Like windmills they use the winds to generate their power.
