What is the gravitational attraction between mass a (200kg) and mass b (500kg)? 12m distance between the two masses.

Fg = 4.63×10^-8 N

Explanation:

The gravitational attraction between two masses m1 and m2 is given by:

Fg = G×m1×m2/(r^2) , where m1 = 200kg ,m2 = 500kg,G is gravitational                                                                                         constant  

then:

Fg = [(6.67408×10-11)(200)(500)] /(12^2)        

    = 4.63×10-8 N  

therefore, the gravitational attraction between the mass is 4.63×10-8 N.                                                                                                                                                                                                

the area between the graph and the t axis

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.