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3 years ago

An observer notices that 12 waves pass by in 4 seconds. What is the frequency of these waves? 0.33 Hz 16 Hz 48 Hz 3 Hz

Physics

1 answer:

Dennis_Churaev [7]3 years ago

8 0

Answer:

Frequency = 3 Hz

Explanation:

Frequency is a measure of Hertz. Recall that Hertz is the unit expressing cycles/second, where one second is the denominator of the fraction for simplicity. If there are 12 waves every four seconds, and one wave represents one cycle, dividing 12 waves by 4 seconds will give the answer of 3 waves (or cycles) per one second.

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Physics help please

zhuklara [117]

Answer: 37.981 m/s

Explanation:

This situation is related to projectile motion or parabolic motion, in which the travel of the ball has two components: x-component and y-component. Being their main equations as follows:

x-component:

$x=V_{o}cos\theta t$ (1)

Where:

$x=52 m$ is the point where the ball strikes ground horizontally

$V_{o}$ is the ball's initial speed

$\theta=0$ because we are told the ball is thrown horizontally

$t$ is the time since the ball is thrown until it hits the ground

y-component:

$y=y_{o}+V_{o}sin\theta t+\frac{gt^{2}}{2}$ (2)

Where:

$y_{o}=120m$ is the initial height of the ball

$y=0$ is the final height of the ball (when it finally hits the ground)

$g=-9.8m/s^{2}$ is the acceleration due gravity

Knowing this, let's start by finding $t$ from (2):

$0=y_{o}+V_{o}sin(0\°) t+\frac{gt^{2}}{2}$ (3)

$0=y_{o}+\frac{gt^{2}}{2}$

$t=\sqrt{\frac{-2 y_{o}}{g}}$ (4)

$t=\sqrt{\frac{-2 (120 m)}{-9.8m/s^{2}}}$ (5)

$t=4.948 s$ (6)

Then, we have to substitute (6) in (1):

$x=V_{o}cos(0\°) t$ (7)

And find $V_{o}$ :

$V_{o}=\frac{x}{t}$ (8)

$V_{o}=\frac{52 m}{4.948 s}$ (9)

$V_{o}=10.509 m/s$ (10)

On the other hand, since we are dealing with constant acceleration (due gravity) we can use the following equation to find the value of the ball's final velocity $V$ :

$V=V_{o} + gt$ (11)

$V=10.509 m/s + (-9.8 m/s^{2})(4.948 s)$ (12)

$V=-37.981 m/s$ (13) This is the ball's final velocity, and the negative sign indicates its direction is downwards.

However, we were asked to find the ball's final speed, which is the module of the ball's final vleocity vector. This module is always positive, hence the speed of the ball just before it strikes the ground is 37.981 m/s (positive).

5 0

3 years ago

Pls help‼️Help me with these questions! :/

TiliK225 [7]

Answer:

No number answer; don't want to pull out a calculator lol

Explanation:

Capacitors are added in parallel; opposite of resistors.

So for 9, add 10 and 2.5 then do ((1/12.5)+(1/.3))^-1.

For 10, add 0.75 and 15 first, then the rest is the same idea as 9.

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3 years ago

Rhythms that occur faster and slower than the beat are. Select one:. a. incorrect. b. not synchronized with the time signature.

zlopas [31]

Rhythms that occur faster and slower than the beat are b.not synchronized with the time signature. The synchronization follows the same beat or rhythm. If the time signature say is lower than the original, then the rhythm should be faster. Otherwise, the rhythm is slower than the original one.

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3 years ago

The orientation of which of the following does not influence the phases of the moon? a. Earth c. Sun b. the moon d. Stars Please

beks73 [17]

I'm pretty sure it's D. The stars don't influence the moon's phases.

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3 years ago

You add 800 ml of water at 20c to 800 ml of water at 80c what is the most likely final temperature of the mixture ?

bekas [8.4K]

Answer:

d. 50 C

Explanation:

In this problem, we have to add 800 ml of water at 20 Celsius to 800 ml of water at 80 Celsius.

According to the 2nd law of thermodynamics, heat transfers from hot to cold temperature.

The quantity of both the different waters is equal so this makes it very easy. All we have to do is find the mean of both the temperatures:

Final temperature = (20 C + 80 C)/2

= 50 Celsius

3 0

3 years ago

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