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3241004551 [841]

3 years ago

11

a sleepy atudent drops a calculator out of a window yhata 20.7 m off the geound. we can ignore air resistance. what js the veloc

ity of the calculator after falling for 1.8 s

1 answer:

frez [133]3 years ago

6 0

The acceleration of gravity is

9.8 m/s^2 down.

When an object falls out of a hand, its speed after 1.8s is

(9.8)x(1.8) = 17.6 m/s down.

It doesn't matter what it is, how much it weighs, or how high it was dropped from.

If it's more than 17.6 m/s, then this happened on a different, bigger planet.

If it's less than 17.6 m/s, then it must have hit something on the way down, like some air or something.

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What kind of wave (transverse of longitudinal) is each of the following and why?

Elina [12.6K]

Answer:

1.) Longitudinal waves

2.) Transverse waves

3.) Longitudinal waves

Explanation:

The sound of one whale calling another whale underwater. is a longitudinal wave since the medium, in this case the body of water, is vibrating parallel to the direction of propagation of the wave.

A pulse sent down a stretched rope by snapping one end of it. ( transverse wave) because its oscillations are perpendicular to the direction of the wave or path of propagation

The vibrations in a guitar string

Longitudinal wave. Because its oscillations are parallel to the direction of the wave or path of propagation

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3 years ago

He distance between two consecutive crests is 2.5 meters. Which characteristic of the wave does this distance represent? amplitu

kupik [55]

Frequency is measured in units of reciprocal time.
Period is measured in units of time.
Phase is a number without units that represents a fraction of a wave.

None of these is measured in meters, so none of them can be the answer.
It must be either amplitude or wavelength.

Amplitude is a quantity that's measured at one or two points in the same wave.
The question is talking about points on consecutive waves.

<em>Wavelength is</em> the only choice left. That must be it.

3 0

2 years ago

Read 2 more answers

The British gold sovereign coin is an alloy of gold and copper having a total mass of 7.988 g, and is 22-karat gold 24 x (mass o

matrenka [14]

Answers:

(a) $0.0073kg$

(b) Volume gold: $3.79(10)^{-7}m^{3}$ , Volume cupper: $7.6(10)^{-8}m^{3}$

(c) $17633.554kg/m^{3}$

Explanation:

<h2>(a) Mass of gold </h2><h2 />

We are told the total mass $M$ of the coin, which is an alloy of gold and copper is:

$M=m_{gold}+m_{copper}=7.988g=0.007988kg$ (1)

Where $m_{gold}$ is the mass of gold and $m_{copper}$ is the mass of copper.

In addition we know it is a 22-karat gold and the relation between the number of karats $K$ and mass is:

$K=24\frac{m_{gold}}{M}$ (2)

Finding ${m_{gold}$ :

$m_{gold}=\frac{22}{24}M$ (3)

$m_{gold}=\frac{22}{24}(0.007988kg)$ (4)

$m_{gold}=0.0073kg$ (5) This is the mass of gold in the coin

<h2>(b) Volume of gold and cupper</h2><h2 />

The density $\rho$ of an object is given by:

$\rho=\frac{mass}{volume}$

If we want to find the volume, this expression changes to: $volume=\frac{mass}{\rho}$

For gold, its volume $V_{gold}$ will be a relation between its mass $m_{gold}$ (found in (5)) and its density $\rho_{gold}=19.30g/cm^{3}=19300kg/m^{3}$ :

$V_{gold}=\frac{m_{gold}}{\rho_{gold}}$ (6)

$V_{gold}=\frac{0.0073kg}{19300kg/m^{3}}$ (7)

$V_{gold}=3.79(10)^{-7}m^{3}$ (8) Volume of gold in the coin

For copper, its volume $V_{copper}$ will be a relation between its mass $m_{copper}$ and its density $\rho_{copper}=8.96g/cm^{3}=8960kg/m^{3}$ :

$V_{copper}=\frac{m_{copper}}{\rho_{copper}}$ (9)

The mass of copper can be found by isolating $m_{copper}$ from (1):

$M=m_{gold}+m_{copper}$

$m_{copper}=M-m_{gold}$ (10)

Knowing the mass of gold found in (5):

$m_{copper}=0.007988kg-0.0073kg=0.000688kg$ (11)

Now we can find the volume of copper:

$V_{copper}=\frac{0.000688kg}{8960kg/m^{3}}$ (12)

$V_{copper}=7.6(10)^{-8}m^{3}$ (13) Volume of copper in the coin

<h2>(c) Density of the sovereign coin</h2><h2 />

Remembering density is a relation between mass and volume, in the case of the coin the density $\rho_{coin$ will be a relation between its total mass $M$ and its total volume $V$ :

$\rho_{coin}=\frac{M}{V}$ (14)

Knowing the total volume of the coin is:

$V=V_{gold}+V_{copper}=3.79(10)^{-7}m^{3}+7.6(10)^{-8}m^{3}=4.53(10)^{-7}m^{3}$ (15)

$\rho_{coin}=\frac{0.007988kg}{4.53(10)^{-7}m^{3}}$ (16)

Finally:

$\rho_{coin}=17633.554kg/m^{3}}$ (17) This is the total density of the British sovereign coin

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3 years ago

The smallest living part that makes up all living things is a

Arturiano [62]

Answer:

cells

Explanation:

they are the smallest living organisms

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3 years ago

What do all types of electromagnetic radiation have in common?

Andrew [12]

<span>They are emitted by the unstable nuclei of certain atoms.
That's all I could find out; Sorry I couldn't be more of an help.</span>

5 0

3 years ago