You are helping a friend moving to the 25th floor of an apartment building. You and your friend are loading on the elevator one of her large moving boxes, having a mass of 25.0 kg. As the elevator is accelerating upward with an acceleration of 3.80 m/s2, you push horizontally on the box. What is the magnitude of the force you should apply so that the box will start to move? Once it began to move, what force magnitude would you need to make it slide at constant speed? The coefficients of friction between the box and the elevator floor are μs = 0.64 and μk = 0.32.

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.

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.

higher potential

explanation:

because it is in a high speed so it must move into a of high potential