Answer:

Explanation:
<u>Given:</u>
- Diameter of the plates of the capacitor, D = 21 cm = 0.21 m.
- Distance of separation between the plates, d = 1.0 cm = 0.01 m.
- Minimum value of electric field that produces spark,

When the dimensions of the plate of the capacitor is comparatively much larger than the distance of separation between the plates, then, according to the Gauss' law of electrostatics, the value of the electric field strength in the region between the plates of the capacitor is given by

where,
= surface charge density of the plate of the capacitor =
.
= magnitude of the charge on each of the plate.
= surface area of each of the plate =
= electrical permittivity of free space, having value = 
For the minimum value of electric field that produces spark,

It is the maximum value of the magnitude of charge which can be added up to each of the plates of the capacitor.
Complete Question
The complete question is shown on the first uploaded image
Answer:
Explanation:
From he question we are told that
The first mass is 
The second mass is 
From the question we can see that at equilibrium the moment about the point where the string holding the bar (where
are hanged ) is attached is zero
Therefore we can say that

Making x the subject of the formula



Looking at the diagram we can see that the tension T on the string holding the bar where
are hanged is as a result of the masses (
)
Also at equilibrium the moment about the point where the string holding the bar (where (
) and
are hanged ) is attached is zero
So basically


Making
subject


Answer:
<em>The range is 35.35 m</em>
Explanation:
<u>Projectile Motion</u>
It's the type of motion that experiences an object projected near the Earth's surface and moves along a curved path exclusively under the action of gravity.
Being vo the initial speed of the object, θ the initial launch angle, and
the acceleration of gravity, then the maximum horizontal distance traveled by the object (also called Range) is:

The projectile was launched at an angle of θ=30° with an initial speed vo=20 m/s. Calculating the range:



The range is 35.35 m
Answer:
2,400kg * m/s
Explanation:
You are missing some information in the question but the rest could be found some where else.
The question gives the masses and starting velocity of each car.
Car 1: m = 600kg and sv = 4m/s
Car 2: m 400kg and sv = 0m/s
Find the momentum of both cars.
Car 1: 600 * 4 = 2400
Car 2: 400 * 0 = 0
Add both.
2400 + 0 = 2400
Best of Luck!