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3 years ago

Please help!

Physics

2 answers:

Marina86 [1]3 years ago

6 0

Answer:

I think It Should be Star B

Explanation:

Oliga [24]3 years ago

6 0

Answer:

Star B

Explanation:

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What is the lowest temperature that a substance can reach

irina1246 [14]

It's known as Absolute Zero. On the Kelvin scale, 0 is the lowest that anything can reach in temperature. It's supposedly impossible to reach, but it's the known limit.

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3 years ago

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Two equal, but oppositely charged particles are attracted to each other electrically. The size of the force of attraction is 48.

galina1969 [7]

Given:

The force of attraction is F = 48.1 N

The separation between the charges is

$\begin{gathered} r=\text{ 60.9 cm} \\ =\text{ 60.9}\times10^{-2}\text{ m} \end{gathered}$

Also, the magnitude of charge q1 = q2 = q.

To find the magnitude of charge.

Explanation:

The magnitude of charge can be calculated by the formula

$\begin{gathered} F=\frac{k(2q)}{r^2} \\ q=\frac{Fr^2}{2k} \end{gathered}$

Here, k is the Coulomb's constant whose value is

$k\text{ = 9}\times10^9\text{ N m}^2\text{ /C}^2$

On substituting the values, the magnitude of charge will be

$\begin{gathered} q=\frac{48.1\times(60.9^\times10^{-2})^2}{2\times9\times10^{^9}} \\ =9.91\times10^{-10}\text{ C} \\ =9.91\times10^{-4}\text{ }\mu C \end{gathered}$

Thus, the magnitude of each charge is 9.91 x 10^(-4) micro Coulombs.

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2 years ago

A man pushes a shopping cart across a level floor. What force resists the effort force? A) gravity B) friction C) the normal for

Kipish [7]

Answer:

B) Friction

Explanation:

Friction is a force that acts when an object is sliding along a surface. Microscopically, this force is due to the fact that the two surfaces are not perfectly smooth, but they have "imperfections" that cause a force that opposes the motion of the object.

For an object sliding on a flat surface, the force of friction has magnitude:

$F_f = \mu_k mg$

where

$\mu_k$ is the coefficient of kinetic friction

m is the mass of the object

g is the acceleration of gravity

The direction of the force of friction is always opposite to the direction of motion of the object.

In reality, friction also acts if the object is at rest and it is pushed by a force; in this case, we talk about static friction, and its magnitude is

$F_f = \mu_s mg$