You have a pumpkin of mass m and radius r. the pumpkin has the shape of a sphere, but it is not uniform inside so you do not know its moment of inertia. in order to determine the moment of inertia, you decide to roll the pumpkin down an incline that makes an angle θ with the horizontal. the pumpkin starts from rest and rolls without slipping. when it has descended a vertical height h, it has acquired a speed of v = √(5gh/4).

find the moment of inertia i of the pumpkin in terms of m and r

less than one you can't create energy

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.

the answer is 100. i just did this lesson and got a 100% on it. : )

-fishtank