A) Water is moving from a point of bigger height to a point of a lower height, This changes the kinetic and potential energies of water. Some of the kinetic energy of water is transfered to a waterwheel. This causes water wheel to spin. Spining waterwheel has rotational energy. Also waterwheel is rotating around certain point. This causes friction and there is frictional energy.
B)To light LED we need electric energy. To create electric energy we need a generator. Generator consists of a rotor (a magnet) and a stator (copper wire). If we attach a magnet to waterwheel and a wire somewhere close to waterwheel the electric energy would be induced. This energy can be used to light LED.
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Answer:
α = -π/3 rad/s²
θ = 1.5π rad ≈ 4.71 rad
θ = 0.75 rev
Explanation:
30 rev/min (2π rad/rev) / (60 s/min) = π rad/s
α = (ωf - ωi) / t = (0 - π) / 3 = -π/3 rad/s²
θ = ½αt² = ½(π/3)3² = 1.5π rad ≈ 4.71 rad
θ = 1.5π rad / 2π rad/rev = 0.75 rev
Answer:
540 nm
Explanation:
According to the question,
The refractive index of the soap bubble, 
.
The thickness of the soap bubble wall is, 
.
Now, for constructive interference of soap bubble.
.
Now for first order m=1.
Therfore,
Substitute all the variables in the above equation.
.
Therefore,
.
Therefore the visible light wavelength which is strongly reflected is 540 nm.
The car's speed is 240km/4hr= 60km/hr.
There's not enough information given in the question to determine its velocity.
