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3 years ago

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Which fundamental force causes some forms of radioactivity? A. Gravity B. Electromagnetic force C. Strong nuclear force D. Weak

nuclear force?

1 answer:

I am Lyosha [343]3 years ago

5 0

Hello.

The answer is: D. weak nuclear force.

The weak force causes beta decay, a form of radioactivity. It could not be explained by the strong nuclear force, the force that’s responsible for holding the atomic nucleus together, because this force doesn’t affect electrons.

It couldn’t be the electromagnetic force, because this does not affect neutrons, and the force of gravity is far too weak to be responsible.

Have a nice day

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When two objects made of different materials are rubbed together, they will attract each other after the charging process.Immers

Sergio039 [100]

Answer:

True

Explanation:

because their is friction(e.g take a ruler rub it in your hair then put it on top of a piece of paper on the table then u will see the process)among the two objects.

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2 years ago

A starship blasts past the earth at 2.0*10^8 m/s .Just after passing the earth, the starship fires a laser beam out its back of

Vilka [71]

Answer:

at the speed of light ( $c=3.0\cdot 10^8 m/s$ )

Explanation:

The second postulate of the theory of the special relativity from Einstein states that:

"The speed of light in free space has the same value c in all inertial frames of reference, where $c=3.0\cdot 10^8 m/s$ "

This means that it doesn't matter if the observer is moving or not relative to the source of ligth: he will always observe light moving at the same speed, c.

In this problem, we have a starship emitting a laser beam (which is an electromagnetic wave, so it travels at the speed of light). The startship is moving relative to the Earth with a speed of 2.0*10^8 m/s: however, this is irrelevant for the exercise, because according to the postulate we mentioned above, an observer on Earth will observe the laser beam approaching Earth with a speed of $c=3.0\cdot 10^8 m/s$ .

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2 years ago

How do the units of work and power compare?

ki77a [65]

Answer:

Option (d) is correct.

Explanation:

Work done is given by :

W = Fd, where F is force and d is displacement

Unit of work done :

The SI unit of force is Newton (N) and that of displacement is meter (m). So, the unit of work done is N-m. It is call Joule. It means that the unit of work done is Joule.

Power is given by rate at which the work is done. It is given by :

P = W/t, W is work done and t is time

Unit of power:

Unit of work is Joule (J) and that of time is second (s). It means that the unit of power is Watt and it is equal to Joule/second

Hence, the correct option is (d) "The unit for work is a joule. The unit for power is a watt, which is a joule per second".

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2 years ago

Why is the law of buoyancy considered a law?

solong [7]

Answer:

Explanation:

because it is a function of physics that will always be true, hope this helps :)

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2 years ago

One string of a certain musical instrument is 70.0 cm long and has a mass of 8.79 g . It is being played in a room where the spe

Svetach [21]

To solve this problem we will apply the concepts of linear mass density, and the expression of the wavelength with which we can find the frequency of the string. With these values it will be possible to find the voltage value. Later we will apply concepts related to harmonic waves in order to find the fundamental frequency.

The linear mass density is given as,

$\mu = \frac{m}{l}$

$\mu = \frac{8.79*10^{-3}}{70*10^{-2}}$

$\mu = 0.01255kg/m$

The expression for the wavelength of the standing wave for the second overtone is

$\lambda = \frac{2}{3} l$

Replacing we have

$\lambda = \frac{2}{3} (70*10^{-2})$

$\lambda = 0.466m$

The frequency of the sound wave is

$f_s = \frac{v}{\lambda_s}$

$f_s = \frac{344}{0.768}$

$f_s = 448Hz$

Now the velocity of the wave would be

$v = f_s \lambda$

$v = (448)(0.466)$

$v = 208.768m/s$

The expression that relates the velocity of the wave, tension on the string and linear mass density is

$v = \sqrt{\frac{T}{\mu}}$

$v^2 = \frac{T}{\mu}$

$T= \mu v^2$

$T = (0.01255kg/m)(208.768m/s)^2$

$T = 547N$

The tension in the string is 547N

PART B) The relation between the fundamental frequency and the $n^{th}$ harmonic frequency is

$f_n = nf_1$

Overtone is the resonant frequency above the fundamental frequency. The second overtone is the second resonant frequency after the fundamental frequency. Therefore

$n=3$

Then,

$f_3 = 3f_1$

Rearranging to find the fundamental frequency

$f_1 = \frac{f_3}{3}$

$f_1 = \frac{448Hz}{3}$

$f_1 = 149.9Hz$

7 0

2 years ago