1. If a force of 40N is applied for 0.2 sec

to change the momentum of a

volleyball, what is the impulse?

J = 8 kg-s

Explanation:

Given that,

Force, F = 40 N

Time, t = 0.2 s

We need to find the impulse. We know that,

Impulse, J = F×t

So,

J = 40 × 0.2

J = 8 kg-s

So, the impulse is 8 kg-s.

potential energy is directly proportional to height.

more height = more potential energy.

greatest increase in height = greatest increase in potential energy

where are the points with the greatest increase in height ?

has to be c-e or d-e .

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.