1' draw a displacement -time graph for the following. displacement (m) 0,20,40,40,80,80,60,40 time (s) 0,10,20,30,40,50,60,70,80. a) explain the different sections of the graph in as much detail as you can. b). use the graph to determine the maximum velocity c) find the average velocity after 45s. d) find the instantaneous velocity at 45s ​

1 - wave length

2 - amplitude

3 - crest

4 - trough

explanation:

duh.

the answer is a. hope this .

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.