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3 years ago

physical changes occur when existing bonds break and new bonds form

1 answer:

6 0

<span>A physical change is any change that alters the form or appearance of a substance but does not change it into another substance
-Some of the physical properties may be altered, but the chemical composition stays the same
-Examples: Bending, Crushing, Cutting, Melting, Freezing, Boiling</span>

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A train accelerated from 5 km/hr in 0.5 hours. what was the rate of acceleration?

Bezzdna [24]

Acceleration is the simply rate of change in velocity, how much faster or slower is the object changing speed with respect to time.

A = v/t = 5 km/hr/0.5 hr

5/1/2 = 5 • 2 = 10 km/hr^2.

This would be the acceleration.

5 0

3 years ago

Is density the degree of compactness of a substance?

san4es73 [151]

Yes it is, in other simplified terms density compares the amount of matter an object has to its volume.

5 0

3 years ago

A wire is oriented along the x-axis. It is connected to two batteries, and a conventional current of 2.4 A runs through the wire

Deffense [45]

Answer:

$\vec{F}=0.40176 N \hat{k}$

Explanation:

To calculate the force we need to use this equation

$\vec{F}=\int\limits^L_0 {i(\vec{dl}\times\vec{B})}$

where L is the total length of the wire

So in this case the small element of current is

$\vec{dl} = dx \hat{i}$

Because x is the direction of the current flow.

As is said in the problem B is such that

$\vec{B} = B \hat{j} = 0.62\hat{j} [ T]$

so to use the equation above we first calculate the following cross product:

$\vec{dl}\times\vec{B}=dx \hat{i}\times B \hat{j} = Bdx\hat{k}$

so the force:

$F = \int\limits^L_0 {i(\vec{dl}\times\vec{B})}=\int\limits^L_0{iBdx\hat{k}}$

So here we use the fact that B=0 in any point of the x axis that is not $x^{'}=0.27 [m]$ , that means that we only need to do the integration between a very short distant behind the point $x^{'}=0.27 [m]$ and a very short distant after that point, meaning:

$\vec{F}= \lim_{h \to 0}{\int\limits^{x^{'}+h}_{x^{'}-h}{iBdx\hat{k}} }$

so is the same as evaluating $iBx$ at $x=x^{'}$

that is:

$2,4 A * 0,62 T * 0,27 m \hat{k}$

$2,4 A * 0,62 (\frac{Kg}{A s^{2}}) * 0,27 m \hat{k}$

$2,4*0,62*2,7 ( \frac{ kgm }{ s^{2} } ) \hat{k}$

$\vec{F}=0.40176 N \hat{k}$

5 0

3 years ago

A stone is thrown vertically upward with an initial speed of 24.7 m/s. Neglect air resistance. The speed of the stone when it is

fredd [130]

Answer:

The speed of the stone when it is 4.66 m higher is 236.057 m/s.

Explanation:

Given the initial velocity and vertical distance, we can use the fourth kinematic equation ( $v^{2} =v_{o}^{2}+2ay$ ) to find v final, or the v to the left of the equal sign. We know $v_{o}$ (initial velocity) is 24.7 m/s, y (change in vertical distance) is 4.66 m, and a is another way to write g (acceleration due to gravity), or 9.8 $m/s^{2}$ .

From here you could plug in the values and solve for v final, but to make the solving process simpler, we can simplify the given equation, <em>then </em>plug in the known values.

To isolate v final, we can take the square root of $v^{2}$ and do the same to the right side of the equation. Therefore, we can find v final with: $v_{o} \sqrt{2ay}$ , where v initial is outside of the square root because it squared...

If we plug in the known values to the simplified equation, we get: $v=24.7m/s*\sqrt{2(9.8m/s)(4.66 m)}$

The final answer is 236.057 m/s.

4 0

2 years ago

A sample of gas is enclosed in a container of fixed volume. Identify which of the following statements are true. Check all that

motikmotik

Answer:

B. If the container is cooled, the gas particles will lose kinetic energy and temperature will decrease.

C. If the gas particles move more quickly, they will collide more frequently with the walls of the container and pressure will increase.

E. If the gas particles move more quickly, they will collide with the walls of the container more often and with more force, and pressure will increase.

#FreeMelvin

7 0

4 years ago

﻿physical changes occur when existing bonds break and new bonds form

physical changes occur when existing bonds break and new bonds form