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3 years ago

Plz. Help. It is due tomorrow.

Physics

1 answer:

AveGali [126]3 years ago

5 0

For no.4 is what seismologists use two main devices to measure an earthquake: a seismograph and aseismoscope. The seismographis an instrument that measures seismic waves caused by an earthquake. The seismographhas three main devices, theRichter Magnitude Scale, theModified Mercalli Intensity Scale, and the Moment-Magnitude Scale.

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Select the correct answer

Nadya [2.5K]

Answer:

$f= 3.0 \times 10 {}^{8} \div 7.0 \times 10 {}^{7} \\ f = 4.28hz$

Given

7 0

3 years ago

Please help me with this!!

Alja [10]

Answer:

Explanation:

Action and Reaction forces are equal in the opposite direction.

3 0

3 years ago

A small sphere of reference-grade iron with a specific heat of 447 J/kg K and a mass of 0.515 kg is suddenly immersed in a water

elena-14-01-66 [18.8K]

Answer:

The specific heat of the unknown material is 131.750 joules per kilogram-degree Celsius.

Explanation:

Let suppose that sphere is cooled down at steady state, then we can estimate the rate of heat transfer ( $\dot Q$ ), measured in watts, that is, joules per second, by the following formula:

$\dot Q = m\cdot c\cdot \frac{T_{f}-T_{o}}{\Delta t}$ (1)

Where:

$m$ - Mass of the sphere, measured in kilograms.

$c$ - Specific heat of the material, measured in joules per kilogram-degree Celsius.

$T_{o}$ , $T_{f}$ - Initial and final temperatures of the sphere, measured in degrees Celsius.

$\Delta t$ - Time, measured in seconds.

In addition, we assume that both spheres experiment the same heat transfer rate, then we have the following identity:

$\frac{m_{I}\cdot c_{I}}{\Delta t_{I}} = \frac{m_{X}\cdot c_{X}}{\Delta t_{X}}$ (2)

Where:

$m_{I}$ , $m_{X}$ - Masses of the iron and unknown spheres, measured in kilograms.

$\Delta t_{I}$ , $\Delta t_{X}$ - Times of the iron and unknown spheres, measured in seconds.

$c_{I}$ , $c_{X}$ - Specific heats of the iron and unknown materials, measured in joules per kilogram-degree Celsius.

$c_{X} = \left(\frac{\Delta t_{X}}{\Delta t_{I}}\right)\cdot \left(\frac{m_{I}}{m_{X}} \right) \cdot c_{I}$

If we know that $\Delta t_{I} = 6.35\,s$ , $\Delta t_{X} = 4.59\,s$ , $m_{I} = 0.515\,kg$ , $m_{X} = 1.263\,kg$ and $c_{I} = 447\,\frac{J}{kg\cdot ^{\circ}C}$ , then the specific heat of the unknown material is:

$c_{X} = \left(\frac{4.59\,s}{6.35\,s} \right)\cdot \left(\frac{0.515\,kg}{1.263\,kg} \right)\cdot \left(447\,\frac{J}{kg\cdot ^{\circ}C} \right)$

$c_{X} = 131.750\,\frac{J}{kg\cdot ^{\circ}C}$

Then, the specific heat of the unknown material is 131.750 joules per kilogram-degree Celsius.

3 0

3 years ago

A cellphone charger has a transformer with 2000 turns in the primary coil which converts 240v a.c to 6v a.c and a rectifier that

inn [45]

Answer:

As we are converting 220V AC into a 5V DC, first we need a step-down transformer to reduce such high voltage. Here we have used 9-0-9 1A step-down transformer, which convert 220V AC to 9V AC. In transformer there are primary and secondary coils which step up or step down the voltage according to the no of turn in the coils.

Selection of proper transformer is very important. Current rating depends upon the Current requirement of Load circuit (circuit which will use the generate DC). The voltage rating should be more than the required voltage. Means if we need 5V DC, transformer should at least have a rating of 7V, because voltage regulator IC 7805 at least need 2V more i.e. 7V to provide a 5V voltage.

5 0

2 years ago

A large spring requires a force of 150 N to compress it only 0.010 m. What is the spring constant of the spring?

soldi70 [24.7K]

Answer:

15000N/m

Explanation:

Given Force F=150 N

compressed distance = 0.010 m

We know that force on a spring due to to compression or elongation is given by $F=kx$ here k is force constant and x is compressed or elongated distance

We have to find force constant

So $F=kx=k\times 0.010$

$k=\frac{150}{0.010}=15000N/m$

8 0

3 years ago