Laquite wants to toss a tennis ball straight up to Michele who is 5 meters above her. If the wants the ball to stop just as it r
1 answer:
Answer:
The initial speed of the tennis ball is 9.89 m/s.
Explanation:
Given that,
Laquite wants to toss a tennis ball straight up to Michele who is 5 meters above her. Final speed of the ball is should be 0. We need to find the initial velocity of the ball. It can be calculated using the conservation of energy as :
So, the initial speed of the tennis ball is 9.89 m/s. Hence, this is the required solution.
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Answer:
a) I = 3.63 W / m² , b) I = 0.750 W / m²
Explanation:
The intensity of a sound wave is given by the relation
I = P / A = ½ ρ v (2π f )²
I = (½ ρ v 4π² s_{max}²) f²
a) with the initial condition let's call the intensity Io
cte = (½ ρ v 4π² s_{max}²)
I₀ = cte s² f₀²
I₀ = cte 10 6
If frequency is increase f = 2.20 10³ Hz
I = constant (2.20 10³) 2
I = cte 4.84 10⁶
let's find the relationship of the two quantities
I / Io = 4.84
I = 4.84 Io
I = 4.84 0.750
I = 3.63 W / m²
b) in this case the frequency is reduced to f = 0.250 10³ Hz and the displacement s = 4 s or
I = cte (f s)²
I = constant (0.250 10³ 4)²
I = cte 1 10⁶
the relationship
I / Io = 1
I = Io
I = 0.750 W / m²