# Is the product of P actually wug and what about

1. May 4, 2012

### Probie1

P = mv so do this mean that the product of v is μg and the product of m is weight?

So it could be written P = wμg

How is this formula derived Vf = √(Vi^2 + (2ad))

2. May 4, 2012

### tiny-tim

Hi Probie1!
Sorry, I've no idea what you're talking about

what is the context (and what do you mean by "product")?

3. May 4, 2012

### Probie1

Does product not mean... umm the make up... it is part of or makes up?
I guess the context of all this is I am trying to undertand how formula's come about.

P = mv so do this mean that the product of v is μg and the product of m is weight?

So it could be written P = wμg

This is another question.

How is this formula derived Vf = √(Vi^2 + (2ad))

4. May 4, 2012

### HallsofIvy

Mathematically "product" means the result of multiplying numbers. It simply doesn't make sense to talk about the "product" of a single number as in "product of v is μg" or "the product of m is weight". Perhaps you mean it the other way- weight is the product of mg. That is "mass times the acceleration due to gravity of an object is the force on that object due to gravity"- by definition its "weight". I'm not sure what you could mean by "v is the product μg", if that is what you intend, because you have not told us what μ is and it is not a standard symbol. Sometimes μ is used for the "coefficient of drag" but that doesn't make sense here. Assuming g is the acceleration due to gravity and v is velocity, their standard meanings, since v would have units of "meters per second" and g "meters per seconds squared", μ would have to have units of "seconds"- it would have to be a "time". Is that correct?

5. May 4, 2012

### Staff: Mentor

What other equations of motion do you know?

6. May 5, 2012

### tiny-tim

Hi Probie1!

(try using the X2 and X2 buttons just above the Reply box )
This is one of the standard equations for constant acceleration.

So we start with a = constant.

Then, integrating, v = at + vi.

And integrating again, d = 1/2 at2 + vit.

Can you finish the proof?

As HallsofIvy says, no.

What did you mean by P m v m and g ?

7. May 5, 2012

### Probie1

D= at + vi2

Alright... stop laughing.

P = momentum
m=mass
v=velocity
g = gravity
μ = friction
w= weight

I thought that if P=mv then v = a = μg but then I remembered where I left my brain because a = change in velocity over a change in time. So it can't possibly be the way I was thinking. So just forget I was so stupid to write that down.

Last edited: May 5, 2012
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