Mathematical problem is classical question

[dE_logics]

From the formula 2as = v² - u²

I made v the subject...and it becomes -

(2as+u²)^1/2 = v


Problem is real world value of 2as is negative...as a result it makes a complex answer...but actually its not; instead the value of v should also come negative.

Here a, u are negative...and a force applies on the body in the same direction as u, which is negative, as a result a negative a cause of that very force.

So the v should also be real and negative...but its coming as complex

Say...can I take the a and u to be positive initially and add the negative sign to the result...sounds ok to me.

 

[Phrak]

$$v=\pm \sqrt{2as+u^2}$$

 

[atyy]

Here a, u are negative...and a force applies on the body in the same direction as u, which is negative, as a result a negative a cause of that very force.

How about the sign of s?

 

[dE_logics]

Yeah its too negative.

But that way the value that comes by is positive, but it should be negative.

 

[davieddy]

Yeah its too negative.

But that way the value that comes by is positive, but it should be negative.

See Phrak's response

 

[ZapperZ]

From the formula 2as = v² - u²

I made v the subject...and it becomes -

(2as+u²)^1/2 = vProblem is real world value of 2as is negative...as a result it makes a complex answer...but actually its not; instead the value of v should also come negative.

Here a, u are negative...and a force applies on the body in the same direction as u, which is negative, as a result a negative a cause of that very force.

So the v should also be real and negative...but its coming as complex

Say...can I take the a and u to be positive initially and add the negative sign to the result...sounds ok to me.

Show this explicitly in a specific problem and we will show you where you forgot another sign somewhere. Both Phrak and atyy have given you sufficient hints.

Zz.

 

[Doc Al]

Problem is real world value of 2as is negative...as a result it makes a complex answer...

When 2as is negative that means the body is slowing down. But a negative value of 2as cannot have a magnitude greater than u²--once the body slows to zero it must reverse direction.

 

[dE_logics]

When 2as is negative that means the body is slowing down. But a negative value of 2as cannot have a magnitude greater than u²--once the body slows to zero it must reverse direction.

It is accelerating, but all the coordinates are negative, I mean...the u, a and s are all negative.

 

[dE_logics]

See Phrak's response

Show this explicitly in a specific problem and we will show you where you forgot another sign somewhere. Both Phrak and atyy have given you sufficient hints.

Zz.

Ok then...both negative and positive results will be valid?...I mean...that's true when a value is squared.

 

[Doc Al]

It is accelerating, but all the coordinates are negative, I mean...the u, a and s are all negative.

So then what is the issue? 2as is positive, thus v² = u² + 2as is positive. No complex answers required.

(Realize that this equation only gives you the magnitude of v; the sign is up to you.)