Alight string is wrapped around a solid cylindrical spool of radius 0.565 m and mass 1.76 kg. a 5.04 kg mass is hung from the string, causing the spool to rotate and the string to unwind. assume that the system starts from rest and no slippage takes place between the string and the spool. use conservation of energy to determine the angular speed of the spool after the mass has dropped 4.19 m. hint: use the relation v=ïr, and use conservation of energy.

this a false

explanation:

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.