An electric ceiling fan with blades 0.750 m in diameter is rotating about a fixed axis with an initial angular velocity of 1.57 rad/s. The angular acceleration is 5.65 rad/s². (a) Calculate the angular velocity at 0.200 s. (b) Through how many revolutions has the blade turned in this time interval (0.200 s)? (c) What is the tangential speed at 0.200 s?

neither accurate nor precise.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.