Answer:
-8.04 m/s2
Explanation:
To find the answer to this, you have to use the 4th kinematic equation:

You plug into the equation to get:

solve for a to get
-8.04 m/s2
The electrostatic force between the two ions is 
Explanation:
The electrostatic force between two charged particle is given by Coulomb's law:

where
is the Coulomb's constant
are the two charges
r is the separation between the two charges
In this problem, the ion of sodium has a charge of

while the ion of chlorine has a charge of

And the distance between the two ions is

Substituting, we find the electrostatic force between the two ions:

where the negative sign simply means that the force is attractive, since the two ions have opposite charge.
Learn more about electrostatic force:
brainly.com/question/8960054
brainly.com/question/4273177
#LearnwithBrainly
You have to use the specific heat equation.
Q = cmΔT where Q is the energy, c is specific heat, m is mass, and ΔT is change in temp.
So we can substitute our variables into the equation.
30000J = (390g)(3.9J*g/C)ΔT
Solving for ΔT, we get:
30000J/[(390g)*(3.9J*g/C) = ΔT
ΔT = 19.72386588C
I'm assuming the temperature is C, since it was not specified.
Hope this helps!
Answer:
<em>Gravity</em><em>.</em><em> </em><em>The</em><em> </em><em>weight-force</em><em> </em><em>or</em><em> </em><em>weight</em><em> </em><em>of</em><em> </em><em>an</em><em> </em><em>object</em><em> </em><em>is</em><em> </em><em>the</em><em> </em><em>force</em><em> </em><em>because</em><em> </em><em>of</em><em> </em><em>Gravity</em><em>,</em><em> </em><em>which</em><em> </em><em>acts</em><em> </em><em>on</em><em> </em><em>the</em><em> </em><em>object</em><em> </em><em>attracting</em><em> </em><em>it</em><em> </em><em>towards</em><em> </em><em>the</em><em> </em><em>centre</em><em> </em><em>of</em><em> </em><em>the</em><em> </em><em>earth</em><em>.</em>
<em>Hope</em><em> </em><em>this</em><em> </em><em>helps</em><em>,</em><em> </em>
<em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em>x</em>
Answer: f=150cm in water and f=60cm in air.
Explanation: Focal length is a measurement of how strong light is converged or diverged by a system. To find the variable, it can be used the formula:
= (nglass - ni)(
-
).
nglass is the index of refraction of the glass;
ni is the index of refraction of the medium you want, water in this case;
R1 is the curvature through which light enters the lens;
R2 is the curvature of the surface which it exits the lens;
Substituting and calculating for water (nwater = 1.3):
= (1.5 - 1.3)(
-
)
= 0.2(
)
f =
= 150
For air (nair = 1):
= (1.5 - 1)(
-
)
f =
= 60
In water, the focal length of the lens is f = 150cm.
In air, f = 60cm.