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2 years ago

Pourquoi doit on toujours préciser le référentiel dans le quel est étudié le mouvement d'un système?

Physics

1 answer:

Vedmedyk [2.9K]2 years ago

4 0

Answer:

The movement of an object depends on the reference frame, so it is important to predicate it.

Explanation:

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Explain the following defects of a simple electric cell:

eimsori [14]

Answer:

Explanation:

The two major defects of simple electric cells causes current supplied to be for short time. These defects are: polarization and local action.

a. Polarization: This is a defect caused by an accumulation of hydrogen bubbles at the positive electrode of the cell. It can be prevented by the use of vent, using a hydrogen absorbing material or the use of a depolarizer.

b. Local Action: This is the gradual wearing away of the electrode due to impurities in the zinc plate. It can be controlled by the amalgamation of the zinc plate before it is used.

4 0

3 years ago

A satellite orbits the earth at a speed of 8.0x 10^3m/s . Calculate the period of orbit of the satellite if the distance between

gladu [14]

Hi there!

The period of an orbit can be found by:

$T = \frac{2\pi r}{v}$

T = Period (? s)
r = radius of orbit (6400000 m)

v = speed of the satellite (8000 m/s)

This is the same as the distance = vt equation. The total distance traveled by the satellite is the circumference of its circular orbit.

Let's plug in what we know and solve.

$T = \frac{2\pi (6400000)}{8000} = \boxed{5026.55 s}$

8 0

1 year ago

he atomic radii of Li and O2- ions are 0.068 and 0.140 nm, respectively. (a) Calculate the force of attraction in newtons betwee

Crazy boy [7]

Answer:

$F = -1.07 *10^{-8} \ N$

$F_r = 1.07 *10^{-8} \ N$

Explanation:

Generally the force of attraction between this two irons is mathematically represented as

$F = \frac{k * [Q_{Li} ] * [Q_{O} ] }{ r^2}$

Here k is known as the proportionality constant with value $k = 2.31 * 10^ {-28} J \cdot m$

substituting -2 for $Q_{O}$ i.e the charge on oxygen , +1 for $Q_{Li}$ i.e the charge on Lithium and $[0.140 + 0.068 ] nm= 0.208 nm = 0.208*10^{-9}$ for r

$F = \frac{ 2.31 * 10^ {-28}* +1 * -2 }{ ( 0.208*10^{-9} )^2 }$

$F = -1.07 *10^{-8} \ N$

Generally the force of repulsion will be the magnitude but different direction to the force o attraction

So Force of repulsionn is

$F_r = 1.07 *10^{-8} \ N$

6 0

3 years ago

The law of universal gravitation states that a gravitational force exists between all objects in the universe. This force is dir

Ber [7]

Answer: D. it has been demonstrated to be without exception under certain stated conditions.

Explanation:

A Law is an affirmation (something established) based on repeated long-term observation of a phenomenon that has been studied and verified.

That is: A law is present in all known theories and therefore is considered universal. In addition, a law can not be refuted, nor changed, because its precepts have been proven through various studies.

Unlike theory, which is the set of rules and principles that describe and explain a particular phenomenon and is subject to changes as new evidence emerges that gives meaning to it.

Then, based on what is explained above, the law of universal gravitation is a statement that exists because it was rigorously tested and verified, therefore it can not be refuted.

3 0

3 years ago

place the compass at one pole of the bar magnet click flip polarity in the menu what happens to the bar magnet and the compass n

Elanso [62]

Answer:

The two poles of the bar magnet change positions. The compass needle spins a half circle.

Explanation:

4 0

3 years ago