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3 years ago

A hot air ballo0n is ascending straight up at a constant

Physics

1 answer:

finlep [7]3 years ago

7 0

Answer: The two places altitudes are: 16.17 m and 40.67 m

Explanation:

Hi!

Lets call z to the vertical direction (z= is ground) . Then the positions of the balloon and the pellet, using the values of the velocities we are given, are:

$z_b =\text{balloon position}\\z_p=\text{pellet position}\\z_b=(7\frac{m}{s})t\\z_p=30\frac{m}{s}(t-t_0)-\frac{g}{2}(t-t_0)^2\\g=9.8\frac{m}{s^2}$

How do we know the value of t₀? This is the time when the pellet is fired. At this time the pellet position is zero: its initial position. To calculate it we know that the pellet is fired when the ballon is in z = 12m. Then:

$t_0=\frac{12}{7}s$

We need to know the when the z values of balloon and pellet is the same:

$z_b=z_p\\(7\frac{m}{s})t =30\frac{m}{s}(t-\frac{12}{7}s)-\frac{g}{2}(t-\frac{12}{7}s)^2$

We need to find the roots of the quadratic equation. They are:

$t_1=2.31s\\t_2=5.81$

To know the altitude where the to objects meet, we replace the time values:

$z_1=16,17m\\z_2=40,67m$

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Answer:

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Explanation:

A)You can choose either because they are the same length and will produce the same wave speed.

B)You should use the heavy rope.

C)You should use the thin cooking twine.

The speed of wave in a string is given by the following formula:

| $v$ | = $\sqrt{\frac{F_T}{u} }$

Where | $v$ | = speed of wave, $F_T$ = tension in the string, and μ = mass per length of the string.

Even though the two strings have the same length, the μ (mass/length) for the heavy rope will be more than the that of a thin rope. Consequently, the $F_T$ :μ for the thin rope will be higher than that of the heavy rope and as such, gives a bigger | $v$ |.

Therefore, the thin rope should be used in order to get a faster wave speed in the telephone.

The correct option is C.

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3 years ago

The sound level of one person talking at a certain distance from you is 61 dB. If she is joined by 5 more friends, and all of th

Lady_Fox [76]

Answer:

Explanation:

For sound level in decibel scale the relation is

dB = 10 log I / I₀ where I₀ = 10⁻¹² and I is intensity of sound whose decibel scale is to be calculated .

Putting the given values

61 = 10 log I / 10⁻¹²

log I / 10⁻¹² = 6.1

I = 10⁻¹² x 10⁶°¹

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intensity of sound of 5 persons

$I=5\times 10^{-5.9}$

$dB=10log\frac{5 X 10^{-5.9}}{10^{-12}}$

= 10log 5 x 10⁶°¹

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sound level will be 67.98 dB .

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3 years ago

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kirza4 [7]

Answer:

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Explanation:

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so here we will have

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3 years ago

A distant planet with a mass of (7.2000x10^26) has a moon with a mass of (5.0000x10^23). The distance between the planet and the

BARSIC [14]

Answer:

Explanation:

This is a simple gravitational force problem using the equation:

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Filling in:

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$F_g=\frac{2.4012*10^{40}}{3.721*10^{23}}$ and now when I divide I will express my answer to the correct number of sig dig's:

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