Why Can't We Rewrite Newton's Second Law as f = m*s/t^2?

[Abhijith S. Raj]

We all know that f = m*a. But why can't we write this as f = m * s/t^2 ?
I know this is wrong. But what is the reason?? Need opinion on this.
Thankyou.

 

[SammyS]

We all know that f = m*a. But why can't we write this as f = m * s/t^2 ?
I know this is wrong. But what is the reason?? Need opinion on this.
Thankyou.

You can't do it because $\displaystyle \ a\ne \frac{s}{t^2} \$ .

 

[Abhijith S. Raj]

a = dv/dt. Ya now i get it.

 

[SammyS]

a = dv/dt. Ya now i get it.

If initial velocity is zero, and acceleration is constant, then the final velocity is v = at, but the average velocity is v/2 . The average velocity multiplied by time gives distance, so that s = (1/2)at*t = (1/2)at², a = 2a/t² .

Therefore, you could write f = 2ma/t², provided that initial velocity is zero, and acceleration is constant.

 

[Abhijith S. Raj]

Thanks

 

[akashpandey]

if accelaration is not constant then?

 

[SammyS]

if acceleration is not constant then?

Then, ... all bets are off. That's also true if the initial (or final) velocity isn't zero.

 

[akashpandey]

sorry but i don't understand.
please can u tell this mathematically. pleasezx