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3 years ago

Which statement best describes what happens when a sound source is moving? (1 point)

Physics

1 answer:

GREYUIT [131]3 years ago

5 0

Answer:

As the sound approaches the observer, the pitch increases; as it passes the observer, the pitch decreases.

Explanation:

The crests come closer when it approaching, and go farther when the source passes the observer.

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Two balls of equal size are dropped from the same height from the roof of a building. One ball has twice the mass of the other.

frutty [35]

Answer:

The kinetic energy of the more massive ball is greater by a factor of 2.

Explanation:

By conservation of energy, we know that the initial energy = final energy. At first, the balls are dropped from a height with no initial velocity so their initial energy is all potential energy. When they reach the bottom, all their energy is kinetic energy. So all of their energy is changed from potential to kinetic energy. This means that the ball with greater potential energy will have a greater kinetic energy.

Potential energy = mgh. Since g = gravity is a constant and h = height is the same, the only difference is mass. Since mass is directly proportional to potential energy, the greater the mass, the greater the potential energy, so the more massive ball has a greater initial potential energy and will have a greater kinetic energy at the bottom.

Additionally, let B1 = lighter ball with mass m and let B2 = heavier ball with mass m2. Since we know that intial potential energy = final kinetic energy. We can rewrite it as potential energy = kinetic energy = mass * gravity constant * height. For B1, it is mgh and for B2 it is 2mgh, so B2's kinetic energy is twice that of B1.

3 0

3 years ago

A 77 turn, 10.0 cm diameter coil rotates at an angular velocity of 8.00 rad/s in a 1.18 T field, starting with the normal of the

Tasya [4]

Answer:

a) fem = 5.709 V, b) t = 0.196 s, c) t = 0.589 s, d) T = 0.785 s

Explanation:

This is an exercise in Faraday's law

fem= - N $\frac{d \Phi _B}{dt}$

fem = - N $\frac{d \ (B A cos \theta)}{dt}$

The magnetic field and the area are constant

fem = - N B A $\frac{d \ cos \ \theta}{dt}$

fem = - N B A (-sin θ) $\frac{d \theta}{dt}$

fem = N B (π d² / 4) sin θ w

fem= $\frac{\pi }{4}$ N B d² w sin θ

with this expression we can correspond the questions

a) the peak of the electromotive force

this hen the sine of the angle is 1

sin θ = 1

fem = $\frac{\pi }{4}$ 77 1.18 0.10² 8.0

fem = 5.709 V

b) as the system has a constant angular velocity, we can use the angular kinematics relations

θ = w₀ t

t = θ/w₀

Recall that the angles are in radians, so the angle for the maximum of the sine is

θ= π/2

t = $\frac{\pi }{2} \ \frac{1}{8}$

t = 0.196 s

c) for the electromotive force to be negative, the sine function of being

sin θ= -1

whereby

θ = 3π/ 2

t = $\frac{3\pi }{2} \ \frac{1}{8}$

t = 0.589 s

d) This electromotive force has values that change sinusoidally with an angular velocity of

w = 8 rad / s

angular velocity and period are related

w = 2π / T

T = 2π / w

T = 2π / 8

T = 0.785 s

6 0

3 years ago

PLEASE ANSWER THESE 2 questions. ASAP!!! Will mark brainiest

arsen [322]

Pretty sure it’s axial because it protects the brain,spinal cord and organs.

6 0

3 years ago

Read 2 more answers

Two boys want to balance a seesaw perfectly. One boy weighs 120 pounds and is sitting four feet from the fulcrum. The other boy

OLEGan [10]

Basically a distance multiplied by a weight that is equal to the distance that is going to be multiplied by the weight. (for the equation we will use X for the distance).

equation: 4 x1 20 = ? x 80

Now step one: 4(120) = X(80)

Or another way is 480 = 80X

480/80 = X

48/8= X

X = 6

I hope this could help! Sorry if it didn't make much sense otherwise!

6 0

3 years ago

I am a bit confused about this question.

gavmur [86]

How do you know when something is moving ? You ALWAYS have to compare it to something else. If the object in question changes its distance or direction from your house, or from your big toe, or from a stake in the ground in your front yard, then you say it's moving. The thing is: There's ALWAYS something else to compare it to.

I assume you're sitting on the couch now, staring at the TV, or at your computer, or at your phone. Compared to the couch, or to the tree in your front yard, or to somebody sitting on top of Mt. Everest, or to downtown Jerusalem, you're NOT moving. Your distance and direction from the reference point isn't changing.

BUT ... what if you compare yourself to somebody sitting at the North pole of the Sun ? He has to keep turning his eyes to watch you (because the Earth including you is in orbit around the sun). So your direction from him keeps changing, and 'relative' to him (compared to him), you're definitely moving.

Now let's go a little farther:

You're sitting in a comfy seat, reading a book that's in your lap. Maybe you're even getting sleepy. You're sitting still in the seat, and the book in your lap isn't moving.

SURPRISE ! Your comfy seat is in Row-27 of a passenger jet, and you're flying to Seattle to visit your Grandma. right now, you're just passing over Casper, Wyoming, and there's somebody down on the ground playing with a telescope. He looks at your airplane, and HE says that you, the seat you're sitting in, and your book are ALL moving at almost 500 miles an hour.

The difference is: YOU're comparing your book to the seat in front of you, and YOU say the book is not moving. The guy with the telescope is comparing the book to the ground he's standing on, and HE says your book is moving west at 500 miles an hour.

You're BOTH correct. The description of ANY motion always depends on what you're comparing to. If you're about to ask "What's the REAL motion of the book ?", then I'm sorry. There's NO SUCH THING as 'REALLY'. It always depends on what you're comparing to. Nine people can be watching the same object, and they can have nine different descriptions of its motion, and they're ALL correct. They're just comparing the object to different things in their own neighborhood, and the nine things are all moving in different ways.

The bottom line: MOTION IS ALWAYS RELATIVE (to something else).

8 0

3 years ago