I need this ASAP
Name the three types of perodic maintenance with examples each.

Predictive maintenance - vibration analysis.

Condition-based maintenance - monitoring pressure reading on Equipment with water systems.

Scheduled maintenance - occurring at repeating intervals is changing a bearing on a conveyor belt every 30 days or inspecting the condition of a motor every 90 days.

Hoping it helps!

i think the answer is a and b

i wish you luck

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.