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3 years ago

A tennis ball is beaten downward with an initial speed of 5 m/s.

Physics

1 answer:

Anastasy [175]3 years ago

4 0

Answer:

Explanation:

Step one:

given data

initial speed u= 5m/s

time t= 3seconds

acceleration due to gravity g= 9.8m/s^2

Required:

the final velocity v

Step two:

applying the first equation of motion

v=u+gt-----------we used + because the ball is falling with gravity

v=5+9.8*3

v=5+29.4

v=34.4

The final velocity is 34.4m/s

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If a voltmeter has a less than ideal resistance, say 1 MΩ, and is used to measure the voltage across a resistor of a comparable

Naddik [55]

Answer:

As the difference between the resistance of voltmeter and the resistance being measured gets reduced the error in the reading of the voltmeter gets increased.

Explanation:

An ideal voltmeter has infinite parallel resistance and because of this it doesn't draw any current from the circuit of measurement which means it will measure the exact voltage across the elements.

But practically speaking, a real voltmeter doesn't has infinite resistance therefore, all the practical voltmeters face loading effect to some extent.

As the difference between the resistance of voltmeter and the resistance being measured gets reduced the error in the reading of the voltmeter gets increased. This is why we want to have a greater value of voltmeter resistance, ideally infinite so that the corresponding error is minimized.

Lets consider the given scenario,

A voltmeter has 1 MΩ parallel resistance and the resistance of of measuring element is 500 kΩ or 0.5 MΩ

lets suppose the supplied voltage is 1 V.

First lets assume that the voltmeter is ideal and it has infinite resistance, so in this case voltmeter will measure a voltage of 1 V across the 0.5 MΩ resistor.

Now consider the loading effect, when we connect the voltmeter across the 0.5 MΩ resistor they both become parallel so the resistance is

R = (1*0.5)/(1+0.5)

R = 0.33 MΩ

As you can see the voltmeter will see a reduced resistance and the corresponding voltage also reduces because resistance and voltage are directly proportional.

Therefore, it is preferred to have a very high parallel resistance of the voltmeter.

8 0

3 years ago

(a) Neil A. Armstrong was the first person to walk on the moon. The distance between the earth and the moon is 3.85 108 m. Find

Goshia [24]

Answer:

It took 1.28 seconds to his voice to reach the Earth via radio waves.

Explanation:

The electromagnetic spectrum is the distribution of radiation due to the different frequencies at which it radiates and its different intensities, that radiation is formed by electromagnetic waves, which are transverse waves formed by an electric field and a magnetic field perpendicular to it.

The distribution of the radiation in the electromagnetic spectrum can also be given in wavelengths, but it is more frequent to work with it at frequencies, the highest being that of gamma rays, followed by X-rays, ultraviolet rays and the visible region , and those of lower frequencies, which correspond to infrared, microwave and radio waves.

Light propagates as electromagnetic wave in vacuum with a speed of $3x10^{8}m/s$ . Therefore, radio waves will have in vacuum the same speed.

Then, to know the time that it took for its voice, the next equation can be used:

$c = \frac{d}{t}$ (1)

Where c is the speed of light, d is the distance and t is the time.

Notice that t can be isolated from equation 1.

$t = \frac{d}{c}$ (2)

$t = \frac{3.85x10^{8} m}{3x10^{8}m/s}$

$t = 1.28s$

Hence, it took 1.28 seconds to his voice to reach the Earth via radio waves.

7 0

4 years ago

To which category does galaxy #1 belong? Why does it belong in this category?

vodka [1.7K]

Answer:

This galaxy belongs to the elliptical galaxy category. This is because it does not have spiral arms.

5 0

3 years ago

Question 2 (1 point)

eduard

Answer: Blake may have a decreased chance of disease.

Explanation:

Research has shown that on average, a person who engages in more physical activity will live longer than a person who does not with one reason for this being that engaging in physical activity helps reduce the risk of diseases such as; heart disease, diabetes, and many forms of cancer.

Obesity (risk factor) and high blood pressure are also reduced by engaging in physical activity.

6 0

3 years ago

Question- Gases the oceans exchange with the atmosphere include..

lutik1710 [3]

I am pretty sure it’s B (carbon dioxide)

5 0

3 years ago