I need help 8th grade science test review will give brainest

A vertical spring with a spring constant of 310 N/m is mounted on the floor. From directly above the spring, which is unstrained

EleoNora [17]

Answer:

7.3cm above the compressed spring.

Explanation:

We can use the conservation energy theorem to solve this problem:

$U_{1}+K_1=U_e+U_2+K_2\\m*g*h+0=\frac{1}{2}k*x^2+0+0\\\\h=\frac{k*x^2}{2*m*g}\\\\h=\frac{310N/m*(3.6*10^{-2})^2}{2*0.28kg*9.8m/s^2}\\\\h=0.073m$

The block was dropped 7.3cm above the compressed spring.

8 0

3 years ago

A backpack has a mass of 8 kg. It is lifted and given 54.9 J of gravitational potential energy. How high is it lifted? Accelerat

sweet [91]

Potencial Energy=hma
Where
Potencial Energy =E= 54.9J
h=?
m=8kg
a=9.8m/s^2
You need to know that 1 J=1(kgm^2)/s^2

Isolate h=E/(ma)
h=(54.9)/(8*9.8)

8 0

3 years ago

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A gas always spreads out to fill all available space.<br> True or False <br> Science Hw

GREYUIT [131]

Answer:

true

Explanation:

i know this im in 6th grade

6 0

3 years ago

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A vessel at rest at the origin of an xy coordinate system explodes into three pieces. Just after the explosion, one piece, of ma

tresset_1 [31]

Answer:

Explanation:

a. Given that:

$m-$ mass of first & second piece, $3m-$ mass of 3rd piece, $\bar v_1$ -velocity of first piece( $-23\dot i \ m/s$ ) and $\bar v_2$ as velocity of 2nd piece ( $-23\dot j \ m/s$ )

Let $\bar v_3$ be velocity of 3rd piece=?

#Vessel is at rest before explosion. Considering conservation of linear momentum:

$m\bar v_1 +m\bar v_2 +3m \bar v_3=0$ #Dividing both sides by $m, m\neq 0$

$\bar v_1+ \bar v_2 +3\bar v_3=0\\3\bar v_3=-(\bar v_1 +\bar v_2)\\\bar v_3=-\frac{1}{3}(\bar v_1 +\bar v_2)$

#Plug the $\bar v_1 ,\bar v_2$ values:

$\bar v_3=-\frac{1}{3}(-23\dot i -23\dot j)=\frac{1}{3}(23\dot i +23\dot j)$

#So the magnitude of the third piece is:

$|\bar v_3|=\sqrt{(23/3)^2+(23/3)^2}\\=10.84m/s$

Magnitude of the 3rd piece is 10.84 m/s

b. To find direction of the magnitude (as an angle relative to the $x$ -axis), we find $\angle \theta$ . The angle is obtained by getting the tan inverse as:

$\theta=tan^-^1(\frac{23/3}{23/3})\\=45\textdegree$

-The direction of the magnitude (angle relative to the x-axis) is 45°

6 0

3 years ago

A bar magnet moves through a loop of wire with constant velocity, and the north pole enters the loop first the induced current w

Ksivusya [100]

<span>A bar magnet moves through a loop of wire with constant velocity, and the north pole enters the loop first the induced current will be greatest when the magnet is located so that </span>the loop is near either the north or the south pole.

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3 years ago

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