Answer:
B. An electric current into a magnetic field
Explanation:
The generation of electrical power requires relative motion between a magnetic field and a conductor. In a generator, mechanical energy is converted into electrical energy. The electricity produced by most generators is in the form of alternating current.
Answer:
Centripetal acceleration.
Explanation:
Centripetal acceleration is a property of a body moving in a uniform circular path and it is directed radially towards the center of the circle in which body is rotating.
The force which causes this acceleration is centripetal force which is also directed towards the center of the circle and pulls the body towards its center.
It is calculated through following formula

where v is velocity and r is the radius of the circle.
Answer:
Explanation:
Given
mass of wheel m=13 kg
radius of wheel=1.8 m
N=469 rev/min

t=16 s
Angular deceleration in 16 s


Moment of Inertia 
Change in kinetic energy =Work done
Change in kinetic Energy

(a)Work done =50.79 kJ
(b)Average Power

Answer:
The SI unit of force is Newton.
Explanation:
Newton is denoted by N.
Force can be defined as the pull or push which change or try to change the state of a body from motion to rest or rest to motion in a straight line.
<h2>
Answer:</h2>
1000th multiple of the standard reference level for intensities.
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Explanation:</h2>
The sound intensity level (β), measured in decibels, of a sound with an intensity of I is defined as follows;
β = 10 log (I / I₀) --------------------(i)
Where;
I₀ = reference intensity
Given from the question;
β = sound level = 30dB
Substitute this value into equation (i) as follows;
30 = 10 log (I / I₀)
Divide both sides by 3;
3 = log (I / I₀)
Take antilog of both sides;
10^(3) = (I / I₀)
1000 = I / I₀
Solve for I;
I = 1000I₀
Therefore the intensity of the sound is 1000 times the standard reference level for intensities (I₀)