The given question is incomplete. The complete question is as follows.
The irregularly shaped area of charge in the figure has surface charge density ηi. Each dimension (x and y) of the area is reduced by a factor of 3.68.
What is the ratio ηf/ηi where ηf is the final surface charge density? I found this value to be 13.5 and it is correct
An electron is very far from the area. What is the ratioFf/Fi of the electric force on the electronafter the area is reduced to the force before the area wasreduced? I found this to also be 13.5, but it is wrong.
Explanation:
Let us consider that expression for area will be as follows.
Area () =
As,
= 13.5
Also, = 1
As the electron is very far from the area. Hence, it can be considered as a point charge. Whereas charge is also constant as the force is not changing.
B - atoms are to small to see
<u>The answer is not contained detail explanation, just a solution and the required values. </u>
All the details are in the pictures, the answers are marked with orange colour.
Note,
in the task no 20.:
V - the velocity of the pair of the balls after collision.
in the task no 21:
m₁ - the mass of the copper ball; m₂ - the mass of the copper calorimeter; m₃ - the mass of the water; t₀ - the initial temperature of water in the copper calorimeter; θ - the final temperature in the calorimeter after the copper ball is transferred into a copper calorimeter; t₁ - the required initial temperature of the copper ball before it is transferred into the calorimeter.
Answer:
<em>They represent kinetic energy</em>
Explanation:
<u>Kinetic Energy
</u>
A body can do work due to some of its attributes or states. For example, its mass can do work if used to provide energy, if the object is at a certain height respect to some reference level, it can do work when going downwards (potential energy), if the object moves at a certain speed, it can do work when transferring part of its speed to other objects. It's called kinetic energy and is given by
Both runners are moving in a horizontal path, thus they have kinetic energy, given by the above equation. If they could jump below ground level, then they will also have potential energy