Answer:

Explanation:
Given that,
The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is given by :

Where
k is the dielectric constant of the substance.
v is the speed of light in water


So, the speed of light in water is 
Answer:
The particle’s velocity is -16.9 m/s.
Explanation:
Given that,
Initial velocity of particle in negative x direction= 4.91 m/s
Time = 12.9 s
Final velocity of particle in positive x direction= 7.12 m/s
Before 12.4 sec,
Velocity of particle in negative x direction= 5.32 m/s
We need to calculate the acceleration
Using equation of motion


Where, v = final velocity
u = initial velocity
t = time
Put the value into the equation


We need to calculate the initial speed of the particle
Using equation of motion again


Put the value into the formula


Hence, The particle’s velocity is -16.9 m/s.
The work done is by the centripetal force on mass m during an angular displacement of 2π revolutions mv²2π /r J
Centripetal force - a force acts on an moving object in circular path.
the centripetal force is given by
F= mv²/r (equation1)
Work done is given by
W = Fd (equation 2)
d = 2π
work is done by the centripetal force on mass m during an angular displacement of 2π revolutions is given by:
to calculate work done using equation 1 in 2 we get
W = mv² d/r
W = mv² × 2π /r J
The work done is by the centripetal force on mass m during an angular displacement of 2π revolutions mv²2π /r J
To know more about centripetal force :
brainly.com/question/13031430
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Given
v = 343 m/s
ac = 5g
ac = 5*9.8 m/s^2
ac = 49 m/s^2
where,
v: velocity
ac = centripetal aceleration
Procedure
We call the acceleration of an object moving in uniform circular motion—resulting from a net external force—the centripetal acceleration ac; centripetal means “toward the center” or “center seeking”.
Formula

The minimum radius not to exceed the centripetal acceleration is 2401 m.
60 days, tell me if I'm correct please.