1-What is the average acceleration of a car that increases its speed from 0m/s to 35m/s in 7.0s? 2-A hiker walks 79.0 m to the right in 12.5 seconds, then turned around and walked 42.0 m to the left in 9.10 seconds. Calculate the magnitude of the hiker's AVERGAGE VELOCITY?
A-5.37 m/s
B-1.71 m/s
C-4.61 m/s
D-6.32 m/s
3-A basketball is dropped off the top of the bleachers at the football field (Hint NGHS is on Earthand falls freely for 27 seconds before hitting the ground. How far (Hint you are looking for a distance) did the basketball fall?

ok

explanation:

e/c, where e is its total energy

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.