-Surgen de una interacción.
-Nunca aparece una sola: son dos y simultáneas.
-Actúan sobre cuerpos diferentes: una en cada cuerpo.
-Nunca forman un par de fuerzas: tienen la misma línea de acción.
-Un cuerpo que experimenta una única interacción no está en equilibrio, pues sobre el aparece una fuerza unica que lo acelera. Para estar en equilibrio se requieren por lo menos dos interacciones.
Las mas importantes son la 2,3,4 característica
Answer:
The angular velocity at the beginning of the interval is
.
Explanation:
Given that,
Angular acceleration 
Angular displacement 
Angular velocity 
We need to calculate the angular velocity at the beginning
Using formula of angular velocity


Where,
= angular acceleration
= angular velocity
Put the value into the formula



Hence, The angular velocity at the beginning of the interval is
.
To solve this problem we will apply the concepts related to the Doppler effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other. Mathematically it can be described as,

Here,
= Frequency of Source
= Speed of sound
f = Frequency heard before slowing down
f' = Frequency heard after slowing down
v = Speed of the train before slowing down
So if the speed of the train after slowing down will be v/2, we can do a system equation of 2x2 at the two moments, then,
The first equation is,



Now the second expression will be,



Dividing the two expression we have,

Solving for v, we have,

Therefore the speed of the train before and after slowing down is 22.12m/s
If the +12V is on one side of the 2.5 ohm R then.............
V = (2.5/8) x 12 otherwise......
V = (5.5/8) x 12