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grandymaker [24]

3 years ago

11

Evelyn meets her friends at a local restaurant 5 km away. Afterwards she stops at the post office which is another 3 km away, bu

t realizes she left the letter she was going to mail at home and goes back to get it. What is her total distance? Displacement?

1 answer:

marissa [1.9K]3 years ago

8 0

16km because she is 8km away and if she goes back it’s gonna be 8km more so it’s 16km

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Likurg_2 [28]

Skates. An object in motion stays in motion unless an equal amount of force is applied back. She put out more force than what she was giving so it pushed her back

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3 years ago

A 0.3-m-radius automobile tire rotates how many revolutions after starting from rest and accelerating at a constant 2.13 rad/s2

Aloiza [94]

Answer:

The automobile tire rotates 91 revolutions

Explanation:

Given;

angular acceleration of the automobile, α = 2.13 rad/s²

time interval, t = 23.2-s

To calculate the number of revolutions, we apply the first kinematic equation;

$\theta = \omega_i \ + \frac{1}{2} \alpha t^2$

the initial angular velocity is zero,

$\theta =0\ + \frac{1}{2} (2.13) (23.2)^2\\\\\theta = 573.2256 \ Rad$

Find how many revolutions that are in 573.2256 Rad

$N = \frac{\theta}{2 \pi} = \frac{573.2256}{2\pi} \\\\N = 91 \ revolutions$

Therefore, the automobile tire rotates 91 revolutions

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4 years ago

Why are microwaves beneficial to use for transmitting information

Darya [45]

Microwaves. Microwave radiation can be used to transmit signals such as mobile phone calls. ... Certain microwave radiation wavelengths pass through the Earth's atmosphere and can be used to transmit information to and from satellites in orbit

5 0

4 years ago

16 grams of ice at –32°C is to be changed to steam at 182°C. The entire process requires _____ cal. Round your answer to the nea

ICE Princess25 [194]

Answer:

12432 cal.

Explanation:

The process to change ice at -32 ºC to steam at 182 ºC can be divided into 5 steps:

1. Heat the ice to 0 ºC, which is the fusion temperature.

2. Melt the ice (obtaining liquid water), which is a process at constant pressure and temperature, so the liquid obtained is also at 0ºC.

3. Heat the liquid water from 0 ºC to 100 ºC, which is the vaporization normal temperature of the water.

4. Vaporization of all the water; this is also a process that occurs at constant pressure and temperature, so the produced steam will be at 100ºC.

5. Heat the steam from 100 ºC to 182 ºC.

Each process has a required energy, and the sum of the energy required for each and all of the steps is the total amount of energy required for the whole process:

$E_T=E_1+E_2+E_3+E_4+E_5$

$E_1$ is a heating process for the ice, so we know that the energy required is proportional to the temperature difference through the specific heat:

$E_1=m*Cp_{sol}*(T_2-T_1)\\E_1=16g*0.5\frac{cal}{gC}*(0-(-32))=256cal$

$E_2$ is a phase change process, so we do not use the specific heat (sensible heat), but the fusion heat (latent heat), so:

$E_{2}=m*dh_{f}={16g*80\frac{cal}{g}}=1280cal$

Analogously,

$E_3=m*Cp_{liq}*(T_3-T_2)=16g*1.00\frac{cal}{gC}*(100-0)C = 1600 cal$

$E_{4}=m*{dh_{vap}}\\\\E_4=16g*540\frac{cal}{g} =8640cal$

$E_{5}=m*Cp_{vap}*(T_{5}-T_{4})\\E_{5}={16g*0.5\frac{cal}{gK}*(182-100)K}=656cal$

Finally, the total energy required is:

$E_T=256cal+1280cal+1600cal+8640cal+656cal\\E_T=12432cal$

8 0

3 years ago

Technician A says that Ohm's law can be used to determine circuit current flow if total circuit resistance and total voltage are

aleksklad [387]

Answer:

Both technician are correct.

Explanation:

Remember that Ohm's Law its a relationship between Voltage (E), Current (I) and Resistance (R) in an electrical circuit. This relationship is defined by the following equation:

V=IR

In Ohm's Law you have 3 variables (V,I,R) and 1 equation. It means that you need to know 2 variables (Whatever 2 variables) to know the third.

Technician A says, in other words, that could calculate the Circuit current flow (I) knowing total circuit resistance (R) and total voltage (E). Note that Technician A knows 2 to 3 variables, then it's possible to use Ohm's Law with the following equation:

$I= \frac{V}{R}$

Technician B says, in other words, that could determine the unknown resistance (R) knowing total current (I) and source voltage (E). Once again, note that Technician B knows 2 to 3 variables, then it's possible to use Ohm's Law with the following equation:

$R=\frac{V}{I}$

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4 years ago