An amusement park designer wants his swing to have a centripetal acceleration of 21 m/s2. If the velocity of the swing is 13 m/s, how long

should the chain on the swing be?

A. 8.5 m

B. 9.5 m

C. 9.0 m

D. 8.0 m

i'm on my way to history not a mistory.

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.

answer///terminator or twilight zone;