A1.8 kg baseball bat is swinging at 42m/s. it hits a 0.2 kg baseball. after the collision, the bat continues at 28 m/s.

Explanation:

The missing question her is: What is the change in momentum of the baseball?

According to the Impulse-Momentum Theorem, we have:

Where:

is the exerted force

is the time interval

is the change in momentum

So, in the case of the bat and the ball we have:

For the bat:

(1)

For the ball:

(2)

Since is the same for both the bat and the ball, their impulses are equal in magnitude but in opposite direction according to Newton's 3rd law of motion. Hence:

(3)

Then:

 (4)

Where:

Being , ,

Being

Then (4) is rewritten as:

 (5)

Since :

 (6)

Isolating :

(7)

(8)

(9)

Now, the change in momentum of the baseball is:

(10)

Substituting (9) in (10):

(11)

Finally:

This is the change in momentum of the baseball. Note it is negative because its initial velocity is greater than its final 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.