a very essential question

[anamakachamanene]

dear all,
I was thinking about the formula F=ma and I don't understand it please help me please!

 

[ieropsaltic]

Newton's law states that the rate of change of momentum of a body is equivalent to the net force applied to it. We know that momentum = m*v, so the force will be F= d(m*v)/dt. For most cases, the mass is costant, leading to the famous F=ma.

 

[zirtapoz]

I still don't understand

easiyl : if you want to accelerate and object than you have to apply force to it.

So it s proportional with its mass. it means F=ma

Also accelaration(a) causes speeding up(higher velocity ) v=at (if initial velocity =0) that means depending on time and accelaration your velocity ll be up or down(including negative accelaration)

exp: if you want to make a car go faster than you have to speed up(giving force)
after accelaration ends(a=0) that means you r giving no force(F) depending on mass you have to give more force (F=ma)

so cool

 

[zirtapoz]

I'm confused. what is momentum here then? is F power? please help.

other definition of force((instant momentum) as described earlier F= d(m*v)/dt)

Assume a hammer moving 1m/sec and 1000 grams when it hits an object it exert a force to object. that means ,t exerts m*v(force to object) and object starts to move (F=ma) if object is 1000 grams than it ll have accelaration of 1 m/sec². Off course time of applied force causes the final velocity. (V=at). we say that momentum is intantious (MassHammer*VelocityHammer=MassObject*VelocityObject) here you can use momentum when you dont know exact force applied.(using velocity and mass)

But as i understood you dont need momentum. So forget about it and think about what i wrote before..

 

[zirtapoz]

Ok. try another way:

acceleration =d(V)/d(t) (means that changes on velocity over time )
F=ma-----> m*d(v)/d(t) (mass * accelaration) from here we say that

F=m*V/d(t) (bold section = momentum. Also d(v)/d(t)=a ) so in other word Force means instant momentum

Theese are just definitions;

So lets go back to F=ma just you asked;

From the formula F=ma if there is any a(a<>0) then F<>0 ok.
that means if F<> 0 and mass isnt changing then a<> 0.. if a<> 0 then from d(V)/d(t) <>0.. it means V is changing by time. and finaly if there is a force that means (F<>0) there should be accelaration(a<> 0) and accelaration means changin velocity.

 

[anamakachamanene]

what is d(V)/d(t)? what do you mean by a<>0? what is <>?

 

[zirtapoz]

what is d(V)/d(t)? what do you mean by a<>0? what is <>?

d(V)/d(t) derivative of velocity over time (Slope of velocity over time)
<> smaller or greater

 

[anamakachamanene]

voltage?!! what is voltage?! is it something like momentum? you didn't say anything about voltage in other posts

 

[zirtapoz]

voltage?!! what is voltage?! is it something like momentum? you didn't say anything about voltage in other posts

Sorry i changed. it should be Velocity.

 

[anamakachamanene]

What is difference between velocity and acceleration and momentum? and what was voltage?

 

[zirtapoz]

What is difference between velocity and acceleration and momentum? and what was voltage?

simply : at start you have 0 m/sec velocity. after time passes(1 sec) if you have a velocity of 10 m/sec than the acceleration of you is 10/1=10

that s all

 

[anamakachamanene]

what is m/sec?!!! oh my god! there's lot to learn! voltage, velocity, acceleration, momentum, even m/sec?!!!!

 

[zirtapoz]

Forget abou tvoltage . it was mistake.

m/sec----> meter / second------> its a unit of velocity. and this topic should end here. Come back again when you have enough knowledge

 

[anamakachamanene]

Dear zirtapoz,

I am a telecommunications engineer! It was just a survey to see how tolerant some people can be, and boy! you are tolerant!!! you could be good teacher. so tell me now, what is voltage?!!!!!! )))

 

[zirtapoz]

Dear zirtapoz,

I am a telecommunications engineer! It was just a survey to see how tolerant some people can be, and boy! you are tolerant!!! you could be good teacher. so tell me now, what is voltage?!!!!!! )))

i was answering another forum, and yours. and both have been mixed velocity became voltage voltage became velocity...