Newton's first law of motion says (in part) that an object in motion will remain in motion at a constant speed and in a straight line if no forces are acting on it. a. applied b. balanced c. unbalanced d. gravitational

Your answer is C. Unbalanced

unbalanced forces change the direction and speed of objects, therefore it would change the constant speed of an object in motion.

Hope this helps u!

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.

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr