Projectiles are objects that are thrown or launched and are only under the influence of . * 6 points A propeller gravity A force pushing it along it's path external forces

Gravity

Explanation:

Projectiles are objects that are thrown or launched and are only under the influence of gravity. When an object is thrown under the action of gravity, it whos projectile motion. The object that is being thrown is called a projectile.

Hence, the correct option is "gravity".

pecialized keyboards

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.