#18). (I think. It's the one that starts with "Compare..."
Gravity ALWAYS attracts.
The force between electric charges can attract or repel ...
it depends whether the charges are the same kind or opposite kinds.
#19).
With both gravity and electric charges, the force between them quickly
becomes weaker when the distance between them increases.
#20).
I don't think it changes.
If the doorknob gets charged by something that TOUCHES it, so that
charges can flow into it from the other object or out of it, then the total
amount of electric charge on it might change. But the question says
that the doorknob is charged by an "electric field", so nothing touched it,
and charges couldn't flow into it or out of it. The only way it got charged
was by the charges it already had in it getting moved around ... electrons
in one part of the knob moving over to the other side. Then it would act
as if it was charged ... if you touched it, you might get zapped.
#21)., #22)., #23).
You're supposed to draw a graph to answer these.
It's a very easy graph to draw, and you should do it.
Label the x-axis 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.
Label the y-axis 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2 .
Put the four points on the graph ... A, B, C, and D.
For each point, the 'battery voltage' is the number on the x-axis
and the 'Current' is the number on the y-axis.
Then draw a line through the points.
When you have the graph to look at, you can easily answer 21, 22, and 23.
24). I'm not sure, and I don't want to guess.
25). Did you ever move a coil of wire near a magnet in class ?
This is the same situation, only the magnet is moving and the wire is still.
The result will be the same.
26). Magnets have two poles that attract
the opposite kind and repel.
Now you copy the map and fill in the other side.
This is a lot of work for 5 points, so I left some parts for you to do.
Another reason I did that is: You'll learn a lot more that way.
The acceleration of the crate is 1.196 m/s².
<h3>What is acceleration?</h3>
This can be defined as the rate of change of velocity.
To calculate the acceleration of the crate, we use the formula below.
Formula:
- a = (F-mgμ)/m................. Equation 1
Where:
- a = acceleration of the crate
- m = mass of the crate
- F = Force applied to the crate
- μ = Coefficient of friction
From the question,
Given:
- m = 225 kg
- F = 710 N
- g = 9.8 m/s²
- μ = 0.20
Substitute the values above into equation 1
- a = [710-(225×9.8×0.20)]/225
- a = (710-441)/225
- a = 269/225
- a = 1.196 m/s²
Hence, The acceleration of the crate is 1.196 m/s²
Learn more about acceleration here: brainly.com/question/460763
speed of balloon which is rising upwards with constant speed is

speed of the camera which is thrown up from the ground

the distance between camera and balloon when it is thrown from the ground

now let say after time "t" the camera is catch by her friend in the balloon
So the position of balloon and camera must be same



Solving above quadratic equation we got

So after t = 0.39 s her friend will get her camera on the balloon.
Answer:
Mendeleev
Explanation:
He discovered the periodic table trying to organize the elements in 1869
Answer:
1.776 x 10^-19 m
Explanation:
Energy, E = 7 TeV
Let λ be the wavelength.
Energy = h c / λ
Where, h is the Planks,s constant and c be the velocity of light
h = 6.63 x 10-^-34 Js
c = 3 x 10^8 m/s
Convert TeV into J
1 TeV = 1.6 x 10^-7 J
So, E = 7 x 1.6 x 10^-7 = 11.2 x 10^-7 J
11.2 x 10^-7 = (6.63 x 10^-34 x 3 x 10^8) / λ
λ = 1.776 x 10^-19 m