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3 years ago

A student hears a police siren. What would change the frequency that the student hears? Check all that apply.

Physics

2 answers:

BlackZzzverrR [31]3 years ago

9 0

Answer:

Explanation:

It's right on Edge

ser-zykov [4K]3 years ago

4 0

A student hears a police siren.

The arithmetic of the Doppler Effect shows that if the distance between
the source and observer is changing, then the observer hears a different
frequency compared to the frequency actually radiating from the source.

Thus the first four choices would cause the student to hear a different
frequency:

-- if the student walked toward the police car
-- if the student walked away from the police car
-- if the police car moved toward the student
-- if the police car moved away from the student

The last two choices wouldn't affect the frequency heard by the student,
since the perceived frequency of a sound doesn't depend on its intensity.

-- if the intensity of the siren increased
-- if the intensity of the siren decreased.

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A 4.75 kg block is sent up a ramp inclined at an angle ????=31.5° from the horizontal. It is given an initial velocity ????0=15.

Colt1911 [192]

Answer:

d = 13.7 m

Explanation:

When block is moving upwards along the inclined plane

then the block is decelerated due to gravity as well as due to friction and speed of the block by which it is projected upwards is given

$v_i = 15 m/s$

deceleration caused to the block due to net force opposite to the motion is given as

$F = - mg sin\theta - \mu mgcos\theta$

$a = \frac{F}{m}$

$a = -g(sin\theta + \mu cos\theta)$

since block is sliding on the inclined plane

so here we can say that the coefficient of the friction must be kinetic friction here

$a = -9.81(sin31.5 + 0.368 cos31.5)$

$a = - 8.2 m/s^2$

now for finding the distance upto which it will stop is given as

$v_f^2 - v_i^2 = 2 a d$

$0 - 15^2 = 2(-8.2) d$

$d = 13.7 m$

8 0

2 years ago

A basketball player standing up with the hoop launches the ball straight up with an initial velocity of v_o = 3.75 m/s from 2.5

denis23 [38]

Answer:

a) The maximum height the ball will achieve above the launch point is 0.2 m.

b) The minimum velocity with which the ball must be launched is 4.43 m/s or 0.174 in/ms.

Explanation:

For the height reached, we use 3rd equation of motion:

2gh = Vf² - Vo²

Here,

Vo = 3.75 m/s

Vf = 0m/s, since ball stops at the highest point

g = -9.8 m/s² (negative sign for upward motion)

h = maximum height reached by ball

therefore, eqn becomes:

2(-9.8m/s²)(h) = (0 m/s)² - (3.75 m/s²)²

h = 0.2 m

To find out the initial speed to reach the hoop at height of 3.5 m, we again use 3rd eqn. of motion with h= 3.5 m - 2.5m = 1 m (taking launch point as reference), and Vo as unknown:

2(-9.8m/s²)(1 m) = (0 m/s)² - (Vo)²

(Vo)² = 19.6 m²/s²

Vo = √19.6 m²/s²

Vo = 4.43 m/s

Vo = (4.43 m/s)(1 s/1000 ms)(39.37 in/1 m)

Vo = 0.174 in/ms

6 0

2 years ago

These illustrate action reaction forces (7 letters)

never [62]

Answer: opposite

Explanation:

Action reaction forces act in opposite direction to each other.

3 0

2 years ago

How much time would it take a fox to accelerate from 2 m/s to 8 m/s at a rate of 2 m/s/s?

faltersainse [42]

Answer:

read below

Explanation:

uh I might be crazy but there is two ways to solve this a simple way and complexish first understand you are using kinematic equations all 4 are valid for this but you need to know which ones the best choice which is vf=vi + at this should solve for time i would do it for you but I find it better when you plug it in your self your learn much better

3 0

2 years ago

Captain Jack Sparrow has been marooned on an island in the Atlantic by his crew, and decides to builda raft to escape. The wind

Marianna [84]

Answer:

d₃ = 37,729 km, θ= 5.1º North of West

Explanation:

This is a velocity addition problem, the easiest way to solve it is to decompose the velocities in a Cartesian system, the x-axis coincides with the West-East direction and the y-axis with the South-North direction

* first displacement is

d₁ₓ = 11 km

* second offset is

cos 6 = d₂ₓ / d₂

sin 6 = d_{2y} / d₂

d₂ₓ = d₂ cos 6

d_{2y} = d₂ sin 6

d₂ₓ = 6 cos 6 = 5.967 km

d_{2y} = 6 sin 6 = 0.6272 km

* third displacement is unknown

* fourth and last displacement

cos (-11) = d₄ₓ / d₄

sin (-11) = d_{4y} / d₄

d₄ₓ = d₄ cos (-11)

d_{4y} = d₄ sin (-11)

d₄ₓ = 21 cos (-11) = 20.61 km

d_{4y} = 21 sin (-11) = -4.007 km

They tell us that at the end of the tour you are back on the island, so the displacement must be zero

X axis

x = d₁ₓ + d₂ₓ + d₃ₓ + d₄ₓ

0 = 11 +5.967 + d₃ₓ + 20.61

d₃ₓ = -11 - 5.967 - 20.61

d₃ₓ = -37.577 km

Y axis

y = d_{1y} + d_{2y} + d_{3y} + d_{4y}

0 = 0 + 0.6272 + d_{3y} -4.007

d_{3y} = 4.007 - 0.6272

d_{3y} = 3.3798 km

This distance can be given in the form of module and angle

Let's use the Pythagorean theorem for the module

d₃ = $\sqrt{d_{3x}^2 + d_{3y}^2}$

d₃ = $\sqrt{37.577^2 + 3.3798^2}$

d₃ = 37,729 km

Let's use trigonometry for the angle

tan θ = d_{3y} / d₃ₓ

θ = tan⁻¹ $\frac{d_{3y}}{d_{3x}}$

θ = tan-1 (-3.3798 / 37.577)

θ = 5.1º

Since the y coordinate is positive and the x coordinate is negative, this angle is in the second quadrant, so the direction given in the form of cardinal coordinates is

θ= 5.1º North of West

3 0

2 years ago