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2 years ago

Sound

2 answers:

4 0

It is a longitudinal wave. In a longitudinal wave the particles of the medium vibrate in a direction parallel to the direction of energy transport. Sound waves are mechanical waves as well as longitudinal waves that require a medium. They do not travel through a vacuum.

Ann [662]2 years ago

3 0

Longitudinal, because the sound can only travel at one direction

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A racquetball strikes a wall with a speed of 30 m/s and rebounds in the opposite direction with a speed of 26 m/s. The collision

Fudgin [204]

Answer:

The average acceleration of the ball during the collision with the wall is $a=2,800m/s^{2}$

Explanation:

Known Data

We will asume initial speed has a negative direction, $v_{i}=-30m/s$ , final speed has a positive direction, $v_{f}=26m/s$ , $\Delta t=20ms=0.020s$ and mass $m_{b}$ .

Initial momentum

$p_{i}=mv_{i}=(-30m/s)(m_{b})=-30m_{b}\ m/s$

final momentum

$p_{f}=mv_{f}=(26m/s)(m_{b})=26m_{b}\ m/s$

Impulse

$I=\Delta p=p_{f}-p_{i}=26m_{b}\ m/s-(-30m_{b}\ m/s)=56m_{b}\ m/s$

Average Force

$F=\frac{\Delta p}{\Delta t} =\frac{56m_{b}\ m/s}{0.020s} =2800m_{b} \ m/s^{2}$

Average acceleration

$F=ma$ , so $a=\frac{F}{m_{b}}$ .

Therefore, $a=\frac{2800m_{b} \ m/s^{2}}{m_{b}} =2800m/s^{2}$

8 0

3 years ago

Positive Charge is distributed along the entire x axis with a uniform density 12 nC/m. A proton is placed at a position of 1.00

lions [1.4K]

Answer:

b. $\Delta KE = 390 eV$

Explanation:

As we know that the electric field due to infinite line charge is given as

$E =\frac{\lambda}{2\pi \epsilon_0 r}$

here we can find potential difference between two points using the relation

$\Delta V = \int E.dr$

now we have

$\Delta V = \int(\frac{\lambda}{2\pi \epsilon_0 r}).dr$

now we have

$\Delta V = \frac{\lambda}{2\pi \epsilon_0}ln(\frac{r_2}{r_1})$

now plug in all values in it

$\Delta V = \frac{12\times 10^{-9}}{2\pi \epsilon_0}ln(\frac{1+5}{1})$

$\Delta V = 216ln6 = 387 V$

now we know by energy conservation

$\Delta KE = q\Delta V$

$\Delta KE = (e)(387V) = 387 eV$

3 0

3 years ago

radio waves travel at the speed of light, 3 x 10^8 m/s. the wavelength of a radio wave record is 200,000,000 hz is?

ludmilkaskok [199]

Answer:

1.5m

Explanation:

Speed of waves is given as the product of the wavelength and frequency. Sometimes when frequency is not given but the period is given, we get the frequency as the reciprocal of the period. The speed of waves is given in m/s, wavelength in m while frequency in Hz.

Speed, s= fw and making w the subject of formula,

$w=\frac {s}{f}$

Substituting 300, 000, 000 m/s for s and 200, 000, 000 for f then we obtain that

$w=\frac {300000000}{200000000}=1.5 m$

6 0

3 years ago

Two billion people jump up in the air at the same time with an average velocity of 7.0 m/sec. If the mass of an average person i

faust18 [17]

Well first of all, you must realize that it depends on how the jumpers are distributed on the earth's surface. If,say, one billion of them are in the eastern hemisphere and the other billion are in the western one, then the sum of all of their momenta could easily be zero, and have no effect at all on the planet. I'm pretty sure what you must have in mind is to consider the Earth to be a block, with a flat upper surface, and all the people jump in the same direction.

average mass per person = 60 kg.
jump velocity = 7 m/s straight up and away from the block, all in the same direction
one person's worth of momentum = (m) (v) = 420 kg.m/s
sum of two billion of them = 8.4 x 10¹¹ kg-m/s all in the same direction

Earth's "recoil" momentum = 8.4 x 10¹¹ in the opposite direction = (m) (v)

Divide each side by 'm' : v = (momentum) / (mass) =

The Earth's "recoil" velocity is (8.4 x 10¹¹) / (5.98 x 10²⁴) =

 1.405 x 10⁻¹³ m/s =

 0.00000000014 millimeter per second

I have no intuitive feeling for this kind of thing, so can't judge whether
the answer is reasonable. But my math and physics felt OK on the
way to the solution, so that's my answer and I'm sticking to it.

4 0

3 years ago

A block slides down a frictionless inclined ramp. If the ramp angle is 17.0° and its length is find the speed of the block as it

SashulF [63]

Answer:

$2.4\sqrt{L}$ where L is the length of the ramp

Explanation:

Let L (m) be the length of the ramp, and g = 9.81 m/s2 be the gravitational acceleration acting downward. This g vector can be split into 2 components: parallel and perpendicular to the ramp.

The parallel component would have a magnitude of

$gsin\theta = 9.81 sin17^o = 2.87 m/s^2$

We can use the following equation of motion to find out the final velocity of the book after sliding L m:

$v^2 - v_0^2 = 2a\Delta s$

where v m/s is the final velocity, $v_0$ = 0m/s is the initial velocity when it starts from rest, a = 2.87 m/s2 is the acceleration, and $\Delta s = L$ is the distance traveled:

$v^2 - 0 = 2*2.87*L$

$v = \sqrt{5.74L} = 2.4\sqrt{L}$

6 0

3 years ago