An alien from the newly discovers planet nine weighs himself on his planet and finds his weight to be 3200 N. When he stoves on earth he once again weighs himself and find his aight to be 800 N. What is the acceleration due to gravity on planet 9?

2.45 m/s²

Explanation:

From the question,

On the Earth

W = mg Equation 1

Where W = weight of the alien on the earth, m = mass of the alien on the earth, g = acceleration due to gravity of the earth.

Make m the subject of equation 1

m = W/g Equation 2

Given: W = 3200 N

Constant: 9.8 m/s²

Substitute these value into equation 2

m = 3200/9.8

m = 326.5 kg.

Similarly,

On planet 9,

W' = mg' Equation 3

Where W' = weight of the alien on planet 9, g' = acceleration due to gravity on planet 9.

make g' the subject of the equation

g' = W'/m Equation 4

Given: W' = 800 N

Substitute into equation 4

g' = 800/326.5

g' = 2.45 m/s²

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.