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4 years ago

11

At a certain distance, the sound intensity level of a dog's bark is 59 dB. At that same distance, the sound intensity of a rock

concert is twenty thousand times that of the dog's bark. What is the sound intensity level of the rock concert

1 answer:

babymother [125]4 years ago

3 0

Answer:

102 dB

Explanation:

Intensity level is given by:

$I(dB)=10log\frac{I}{I_o}$

$59=10log\frac{I_d}{I_o}\\I_d=10^{5.9}I_o$

$I_r=2\times10^4I_d=2\times10^4\times10^{5.9}I_o$

$I_r(dB)=10log\frac{I_r}{I_o}\\=10log\frac{2\times 10^{9.9}I_o}{I_o}=10\times10.2\\=102 dB$

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A baseball has a mass of 0.15 kg. The baseball is pitched so that it is 1 meter above home plate and moving at 40 m/s. What is t

viktelen [127]

Answer:

K.E = 120 Joules.

Explanation:

<u>Given the following data;</u>

Mass = 0.15kg

Distance = 1m

Velocity = 40m/s

To find kinetic energy;

Kinetic energy can be defined as an energy possessed by an object or body due to its motion.

Mathematically, kinetic energy is given by the formula;

$K.E = \frac{1}{2}MV^{2}$

Where;

K.E represents kinetic energy measured in Joules.

M represents mass measured in kilograms.

V represents velocity measured in metres per seconds square.

Substituting into the equation, we have;

$K.E = \frac{1}{2}*0.15*40^{2}$

$K.E = 0.075*1600$

<em>K.E = 120 Joules.</em>

<em>Therefore, the kinetic energy of the baseball is 120 Joules. </em>

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3 years ago

An airplane in level flight travels horizontally with a constant eastward acceleration of 8.50 m/s2 and a constant northward acc

zloy xaker [14]

Answer:

$d = 3574.3 m$

Explanation:

Given that acceleration of the airplane is

$a_x = 8.50 m/s^2$

$a_y = -28 m/s^2$

initial velocity is given as

$v_x = 83.5 m/s$

$v_y = -15.5 m/s$

now we have displacement in x direction given as

$x = v_x t + \frac{1}{2}a_x t^2$

$x = (83.5)(14) + \frac{1}{2}(8.5)(14)^2$

$x = 2002 m$

Displacement along y direction is given as

$y = v_y t + \frac{1}{2}a_y t^2$

$y = (-15.5)(14) + \frac{1}{2}(-28)(14^2)$

$y = -2961 m$

so the magnitude of the displacement is given as

$d = \sqrt{x^2 + y^2}$

$d = \sqrt{2002^2 + 2961^2}$

$d = 3574.3 m$

7 0

4 years ago

How can you find the net force if two forces act in opposite directions?

Tresset [83]

Then the magnitude of the net force is the difference between the two forces,
and its direction is the same as the direction of the greater one.

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3 years ago

For sprinters running at 12 m/s around a curved track of radius 26 m, how much greater (as a percentage) is the average total fo

Snezhnost [94]

Answer:

114.86%

Explanation:

In both cases, there is a vertical force equal to the sprinter's weight:

Fy = mg

When running in a circle, there is an additional centripetal force:

Fx = mv²/r

The net force is found with Pythagorean theorem:

F² = Fx² + Fy²

F² = (mv²/r)² + (mg)²

F² = m² ((v²/r)² + g²)

F = m √((v²/r)² + g²)

Compared to just the vertical force:

F / Fy

m √((v²/r)² + g²) / mg

√((v²/r)² + g²) / g

Given v = 12 m/s, r = 26 m, and g = 9.8 m/s²:

√((12²/26)² + 9.8²) / 9.8

1.1486

The force is about 114.86% greater (round as needed).

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3 years ago

Benjamina started her walk from the front door of her ground floor apartment. She walked 6 meters to the corner of the building

Cloud [144]

The distance is the total distance she walked which is 16 meters adding the 6 meters to the corner and 10 meters to her friend's apartment. Her displacement is the distance from her original starting point so you set up a triangle with side lengths of 6 and 10 and solve for the hypotenuse which gives you a displacement of 11.66 meters.

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4 years ago

Read 2 more answers