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4 years ago

What is an example of frequency

2 answers:

6 0

'Frequency' is a word that often confuses some people ... for no good reason.
It just means "frequent-ness" or "often-ness" ... how often something happens.

The SI unit of frequency is the Hertz (Hz). Hz means 'per second'.
So " 13 Hz " means 13 per second.

Here are examples of frequency:

-- 780 kilohertz (on your AM radio dial)
-- 98.7 Megahertz (on your FM dial)
-- 5.8 Gigahertz
-- twice a day
-- three per week
-- every 6 months

vaieri [72.5K]4 years ago

3 0

For example 75 Hertz means that there are 75 wave tops per second in for example a radio signal.

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A 69 g particle is moving to the left at 25 m/s . How much net work must be done on the particle to cause it to move to the righ

LekaFEV [45]

Answer:11.59 J

Explanation:

Given

mass of Particle $m=69 gm$

Initially Particle moves towards left $v_1=25 m/s$

Final velocity of Particle is towards Right $v_2=31 m/s$

According to Work Energy theorem

Work done by all the Forces=change in Kinetic Energy

Work done by Force $=\frac{mv_2^2}{2}-\frac{mv_1^2}{2}$

$W=\frac{69\times 10^{-3}}{2}\left [ 31^-25^2\right ]$

$W=\frac{69\times 10^{-3}}{2}\left [ 961-625\right ]$

$W=11.59 J$

5 0

4 years ago

The positions of the consellations appear to change throughout the year because

slava [35]

The earth is revolving around the sun and when the seasons change the earth tilts at a different angle and it changes your perspective on the constellations<span />

8 0

3 years ago

A mercury thermometer is constructed as

Tamiku [17]

Answer:

The change in height of the mercury is approximately 2.981 cm

Explanation:

Recall that the formula for thermal expansion in volume is:

$\frac{\Delta V}{V_0} =\alpha_V\, \Delta\, T\\\Delta V = V_0\,\, \alpha_V\,\,\Delta C$

from which we solved for the change in volume $\Delta V$ due to a given change in temperature $\Delta T$

We can estimate the initial volume of the mercury in the spherical bulb of diameter 0.24 cm ( radius R = 0.12 cm) using the formula for the volume of a sphere:

$V_0=\frac{4}{3} \pi \, R^3\\V_0=\frac{4}{3} \pi \, (0.12\,cm)^3\\V_0=0.007238\,cm^3$

Therefore, the change in volume with a change in temperature of 36°C becomes:

$\Delta V = V_0\,\, \alpha_V\,\,\Delta C\\\Delta V = 0.007238229\, cm^3\,(0.000182)\,(36)\\\Delta V=0.0000474248\, cm^3$

Now, we can use this difference in volume, to estimate the height of the cylinder of mercury with diameter 0.0045 cm (radius r= 0.00225 cm):

$V_{cyl}=\pi r^2\,h\\h =\frac{V_{cyl}}{\pi r^2} \\h=\frac{0.0000474248\, cm^3}{\pi \, (0.00225\,cm)^2} \\h=2.98188 \,cm$

8 0

3 years ago

?a wire is stretched 30% what is the percentage change in resistance

Marat540 [252]

Answer:

The percentage change in resistance of the wire is 69%.

Explanation:

Resistance of a wire can be determined by,

R = (ρl) ÷ A

Where R is its resistance, l is the length of the wire, A its cross sectional area and ρ its resistivity.

When the wire is stretched, its length and area changes but its volume and resistivity remains constant.

$l_{o}$ = 1.3l, and $A_{o}$ = $\frac{A}{1.3}$

So that;

$R_{o}$ = (ρ $l_{o}$ ) ÷ $A_{o}$ = (ρ × 1.3l) ÷ ( $\frac{A}{1.3}$ )

= (1.3lρ) ÷ ( $\frac{A}{1.3}$ )

= $(1.3)^{2}$ × [(ρl) ÷ A]

= 1.69R (∵ R = (ρl) ÷ A)

$R_{o}$ = 1.69R

Where $R_{o}$ is the new resistance, $l_{o}$ is the new length, and $A_{o}$ is the new area after stretching the wire.

The change in resistance of the wire = $R_{o}$ - R

= 1.69R - 1R

= 0.69R

The percentage change in resistance = $\frac{0.69R}{R}$ × 100

= 0.69 × 100

= 69%

The percentage change in resistance of the wire is 69%.

3 0

3 years ago

A 19 kg solid disk of radius0.44 m is rotated about an

Vlad1618 [11]

Answer:

0.915 Nm

Explanation:

1 revolution = 2π rad

We can use the following equation of motion to find out the acceleration acting on the disk

$\omega^2 - \omega_0^2 = 2\alpha\Delta \theta$

where $\omega v = 2.5 rad/s is the final angular velocity of the disk, [tex]\omega_0$ = 0 rad/s is the initial velocity of the can when it starts from rest, $\Delta \theta$ is the angular distance traveled, $\alpha$ is the angular acceleration of the disk, which we care looking for: