Answer:
x = 12cm
Explanation:
First, with the values given for the force and the displacement, you calculate the spring-constant of the dynamometer by using the following equation (primero, con los valores dados de la fuerza y el desplazamiento, calculas la constante del resorte aplicando la siguiente formula):

F: force (fuerza) = 10N
k: spring constant (constante del resorte)
x: displacement of the spring (desplazamiento del resorte) = 6cm
by using these values you calculate k (usando estos valores calculas k):

With this value you calculate the displacement for a force of 20N (con este valor de k calculas el desplazamiento del resorte para una fuerza de 20N):

hence, the displacement is 12cm
Answer:
e) A changing magnetic field produces an electric field.
Explanation:
Ok, we start with a magnetic field and let's study how it affects the motion of a single electron. As the magnetic field changes, it will cause an electromotive force, that moves the electron, and because now we have a moving electron, now we will have an electric field. (Such that the direction of the electromotive force opposes the direction in which the magnetic field changes). This also can be deduced if we look at the third Maxwell's equation:
dE/dx = -dB/dt
This says that the spatial change in an electric field depends on how the magnetic field changes as time pass.
Then the correct option is e) A changing magnetic field produces an electric field.
The radiations detected by Arno Penzias and Robert Wilson
were the original heat from the Big Bang.
Today, we call those waves the "Cosmic Microwave Background".
I'm not sure, but I think those guys were awarded a Nobel Prize in Physics
for that discovery.
Answer:
The element "AI" has:
Protons: 13 Neutrons: 14 Electrons: 13
Have a great day.