Two people are pushing a couch from the same side. One person pushes with a force of 2 N. The other person pushes with a force of 4 N.

a) The couch will move with a force of 8 N.
b) The couch will move with a force of 2 N.
c) The couch will not move.
d) The couch will move with a force of 6 N.

the answer is letter d because both of them are pushing the couch in the same direction so 4 plus 2 will give you 6N

answer: i'm not sure which is which for i get confused on it all the time but i can tell you that the answer lies with the convex and concave devices. i hope this you. have a good day and best of luck to you!

explanation:

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.