A 2455 kg car was pushed by 77 kg student with a force of 720 N. What force does the car apply on the student? a.0 N
b.-797 N
c.- 720 N
d.-3175 N

C

Explanation:

Given that a 2455 kg car was pushed by 77 kg student with a force of 720 N.

According to Newton's third law of motion which state that in every action, there will be equal and opposite reaction.

The action on the car = 720 N

The reaction from the car = - 720 N

Therefore, the force the car will apply on the student will be -720N.

The correct answer is C

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.