Acar moves to the right as shown. in order for the
car to slow down, the acceleration must
1.be less than the car’s velocity
2. point to the left
3. point to the right
4. be equal to zero

1

Explanation:

The car's acceleration must be equals to or less than the car's velocity, cause of the change in velocity.

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.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it