You and a friend are playing with a Hoop to demonstrate some ideas of Rotational Physics. First, though, you want to calculate the Rotational Kinetic Energy of the Hoop as it rolls down a sidewalk without slipping. This means it has both linear kinetic energy and rotational kinetic energy. See a video of Hoop Rolling here. A Hoop can be modeled as a Hoop rotating about its axis through the center of the cylinder. This Hoop has a mass of 0.39 kg and a radius of 0.270 m. You'll need to look up the equation for the Moment of Inertia in your textbook. It is rotating with an angular velocity of 17.0 radians / second in the counter-clockwise (or positive) direction. You can use this to determine the linear velocity of the hoop (since it is rolling without slipping). What is the Total Kinetic Energy of the Hoop

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary 

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.