1.) I’m bored, so I decide to play catch by myself. I throw a 1.5kg ball in the air at 25 m/s. How long do I have to wait to catch it? 2.) I shoot a high velocity rifle in the air at an airplane. The plane is flying at 10000. m. The bullet leaves the rifle at 215 m/s. Can I hit the plane

1) 5 seconds

2) No

Explanation:

1) When you catch the ball, it returns to its initial height, so the displacement is 0.

Given:

Δy = 0 m

v₀ = 25 m/s

a = -10 m/s²

Find: t

Δy = v₀ t + ½ at²

0 m = (25 m/s) t + ½ (-10 m/s²) t²

0 = 25t − 5t²

0 = 5t (5 − t)

t = 5

2) At the maximum height, the vertical velocity is 0 m/s.

Given:

v₀ = 215 m/s

v = 0 m/s

a = -10 m/s²

Find: Δy

v² = v₀² + 2aΔy

(0 m/s)² = (215 m/s)² + 2 (-10 m/s²) Δy

Δy ≈ 2310 m

No, the bullet cannot reach the plane.

it takes about 30 days for it to break down

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.