M, a solid cylinder (m=2.39 kg, r=0.123 m) pivots on a thin, fixed, frictionless bearing. a string wrapped around the cylinder pulls downward with a force f which equals the weight of a 0.870 kg mass, i. e., f = 8.535 n. calculate the angular acceleration of the cylinder.

The angular acceleration of the cylinder is 58.06 rad/s².

Explanation:

Given that,

Mass

Radius

Force

Weight

We need to calculate the angular acceleration of the cylinder

Using formula of torque

Where, F = force

r = radius

m = mass

Put the value into the formula

Hence, The angular acceleration of the cylinder is 58.06 rad/s².

car a and b are moving in opposite directions

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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.