Derive the force equation and ohm's law?

Question

Derive the force equation and ohm's law?

Answer 1

Force is defined as the rate of change in momentum.



Momentum is simply defined as the product of mass and velocity.



momentum = mass, m * velocity,v



Thus, momentum = mv



This means that momentum is a quantity that is dependent on and proportional to mass and velocity.



Once again:



Force is defined as the rate of change in momentum.



Therefore, change in momentum = (mv2 - mv1) ........ equation (i)



where

v2 = final velocity

v1 = initial velocity



Rate means how fast or slow - which means a quantity divided by time or "the change in time".



So, the rate of change in momentum is



equation (i) / time,t



that is



(mv2 - mv1) / t



Taking m (the common factor) out from the equation



Force, F = m(v2 - v1) / t



ie



Force, F = m * (v2 - v1)/t........equation (ii)



Acceleration, a, is defined as the rate of change in velocity ie



a = (v2 - v1) / t................ equation (iii)



Substituting equation (ii) into equation (iii), we get



F = m * a



F = ma



Hence, the equation for force is mass * acceleration

Answer 2

Force = Mass x Acceleration



Current = Voltage / Resistance



It goes something like this: Current induced in a circuit is directly proportional to voltage and inversely proportional to resistance.

Answer 3

O hms law states that the current passing through a metallic conductor at constant temp is prorportional to the potential difference between it's ends.therefore:

v=IR

I=R/V

They're lots of force equations to use depending on the problem.

F=Ma

Where m is mass,a is acceleration,f is force

F=Mg

Where g is gravity

F=Kmv-mu/t

F=km(v-u)/t

if k=1 and m is constant v-u/t=a from the first equation of motion,it implies that F=ma

hope i helped?

Answer 4

The above answers were statements of the force law and Ohm's Law. It fact, the force law, F=ma, comes from the physical observation of the action of massive bodies under the influence of an external force, and is not derived from any other equation. It is one of the 3 basic assumptions of Newton.



Ohm's Law states that the current in a circuit is proportional to the applied voltage I = V/R, where R is the proportionality constant. This can be derived from the force law by considering the action of individual electrons under the influence of the Lorentz force, q(E+vxB), where q is the charge, E the applied electric field, B the magnetic field, and v the electron velocity. As the electron moves in the material, for example copper wire, it is slowed down by collisions with atoms. Assuming the net drag is proportional to v, Ohm's Law can be derived.



A derivation of Ohm's Law in this manner can be found at http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html#c1