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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?????

Respuesta :

MathPhys

Answer:

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.

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