Wind turbines work on a simple principle: instead of using electricity to make wind—like a fan—wind turbines use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.
Answer:
64.945 miles per hour
Explanation:
Since the frequency of sound heard is higher than actual frequency, the ambulance is moving towards you!
The frequency of sound waves as heard from a distance for a sound wave coming towards one at v₀ m/s and whose real frequency is f₀ is given by
+f = f₀/[1 - (v₀/v)]
+f = frequency of sound as heard from the distance away = 8.61 KHz
f₀ = real frequency of sound = 7.87 KHz
v₀ = velocity at which the sound source is moving towards the reference point = ?
v = velocity of sound waves = 343 m/s
8.61 = 7.87/(1 - (v₀/v))
1 - (v₀/343) = 0.9141
v₀/343 = 1 - 0.9141 = 0.0859
v₀ = 343 × 0.0859 = 29.48 m/s = 64.945 miles per hour
Detergents are special, powerful cleansers that can break up dirt, oils, and grease in clothing or on dishes.
Cleaning solvents are used to remove oil, grease, solder flux, and other contaminants.
Acid cleaners are generally used to remove mineral deposits and are useful for descaling dishwashers or removing rust from restroom facilities.
Abrasive uses
* Buffing.
* Honing.
* Drilling.
* Grinding.
* Sanding.
* Polishing.
* Cutting.
* Sharpening.
Answer:
(a) 3.24 w (b) 44.44 ohm
Explanation:
It is given that car draws 0.27 A current so current I = 0.27 A
The system has a voltage of 12 V
(a) Electrical power = voltage ×current 
(b) The resistance is defined as the ratio of voltage and current
So resistance 
Because: Some of the work done by the machine is used to overcome the friction created by the use of the machine. ... Work output can never be greater than work input. Machines allow force to be applied over a greater distance, which means that less force will be needed for the same amount of work.
