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3 years ago

A runner moves west with an initial velocity of 4 m/s. She accelerates 3 m/s2 for 30 seconds. The runner's final velocity is

Physics

1 answer:

Firlakuza [10]3 years ago

3 0

Answer:

v = 94m/s

Explanation:

Using the first equation of motion

v = u + at

u = 4m/s , a = 3m/s² , t = 30s , v = ?

v = u + at

v = 4 + 3 × 30

v = 4 + 90

v = 94m/s

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4. A light string is attatched to a heavy rope, and the whole thing is pulled tight. A wave is sent along the light string. When

ale4655 [162]

Answer:

The correct answer to the question is (A)

When it hits the heavy rope, compared to the wave on the string, the wave that propagates along the rope has the same (A) frequency

Explanation:

The speed of a wave in a string is dependent on the square root of the tension ad inversely proportional to the square root of the linear density of the string. Generally, the speed of a wave through a spring is dependent on the elastic and inertia properties of the string

$v = \sqrt{ \frac{T}{\mu } } = \sqrt{ \frac{T}{m/L } }$

Therefore if the linear density of the heavy rope is four times that of light rope the velocity is halved and since

v = f×λ therefore v/2 = f×λ/2

Therefore the wavelength is halved, however the frequency remains the same as continuity requires the frequency of the incident pulse vibration to be transmitted to the denser medium for the wave to continue as the wave is due to vibrating particles from a source for example

7 0

3 years ago

A 10.0 L tank contains 0.329 kg of helium at 28.0 ∘C. The molar mass of helium is 4.00 g/mol . Part A How many moles of helium a

nadya68 [22]

Answer:

82.25 moles of He

Explanation:

From the question given above, the following data were obtained:

Volume (V) = 10 L

Mass of He = 0.329 Kg

Temperature (T) = 28.0 °C

Molar mass of He = 4 g/mol

Mole of He =?

Next, we shall convert 0.329 Kg of He to g. This can be obtained as follow:

1 Kg = 1000 g

Therefore,

0.329 Kg = 0.329 Kg × 1000 g / 1 Kg

0.329 Kg = 329 g

Thus, 0.329 Kg is equivalent to 329 g.

Finally, we shall determine the number of mole of He in the tank. This can be obtained as illustrated below:

Mass of He = 329 g

Molar mass of He = 4 g/mol

Mole of He =?

Mole = mass / molar mass

Mole of He = 329 / 4

Mole of He = 82.25 moles

Therefore, there are 82.25 moles of He in the tank.

8 0

3 years ago

Which part of a laser printer applies a positive charge to the paper that attracts the toner particles to it

Shalnov [3]

The part of laser printer that applies a positive charge to the paper in order to attract the toner particles is known as transfer roller.

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What is a laser printer:

A laser printer is a kind of printer that uses the electrostatic digital printing process to perform printing. It makes use of the static electricity and toner powder in place of liquid ink.

The toner is applied to specific areas which are dependent on the charge difference created or on the static electricity.

Following are the components of a laser printer:

Scanning unit:

This unit of a laser printer generally consists of a laser diode, a

scanning motor and a polygon mirror.
It also consists of two-beam alignment lenses.

Cartridge unit:

This unit of laser printer consists of three drums, namely primary

charging roller (PCR), organic photoconductive drum (OPC) , and

image transfer roller (ITR).
The transfer roller is also present at a close vicinity of the

printer's toner cartridge.

Fuser assembly unit:

This unit of laser printer consists of a pressure roller and a fuser roller, where the fuser roller assembly consists of a heating

element.

Therefore, the transfer roller unit of a laser printer applies a positive charge to the paper that attracts the toner particles to it.

Learn more about laser printers here:

<u>brainly.com/question/5039703</u>

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6 0

2 years ago

Which qualifications are typical for a Manufacturing career? Check all that apply.

kicyunya [14]

D should be the answer

8 0

3 years ago

A violin string vibrates at 260 Hz when unfingered. At what frequency will it vibrate if it is fingered one fourth of the way do

Advocard [28]

Answer:

346.66 Hz

Explanation:

$l_1$ = Length of string which is unfingered = l

$l_2$ = Length of string which is vibrate when fingered = $l-\dfrac{1}{4}l=\dfrac{3}{4}l$

$f_1$ = Unfingered frequency = 260 Hz

$f_2$ = Fingered frequency

Frequency is inversely proportional to length

$f=\dfrac{1}{l}$

So,

$\dfrac{f_1}{f_2}=\dfrac{l_2}{l_1}\\\Rightarrow \dfrac{f_1}{f_2}=\dfrac{\dfrac{3}{4}l}{l}\\\Rightarrow \dfrac{f_1}{f_2}=\dfrac{3}{4}\\\Rightarrow f_2=\dfrac{4}{3}f_1\\\Rightarrow f_2=\dfrac{4}{3}260\\\Rightarrow f_2=346.66\ Hz$

The frequency of the fingered string is 346.66 Hz

3 0

3 years ago