# Derive the equation

1. Oct 4, 2013

### Marcsmeets

1. The problem statement, all variables and given/known data

Derive the equation v^2 = u^2 + 2as

I have no clue how to do this please can someone help!

Thank you!

2. Oct 4, 2013

### barryj

Notice that there is no t involved in this relationship. Look at your equations for distance and average acceleration and see how to eliminate t.

3. Oct 4, 2013

### Staff: Mentor

I don't know about you, but whenever I see velocity-squared terms I tend to think about kinetic energy...

4. Oct 4, 2013

### barryj

gneill, I am sure you are correct but you can also derive this equation from two basic equations and energy principals are not required.

5. Oct 4, 2013

### Staff: Mentor

Sure. But it's nice to have options. Some approaches are more intuitively obvious to different people.

6. Oct 4, 2013

### barryj

If you use energy, then you have to introduce mass and this is not necessary.

7. Oct 4, 2013

### Staff: Mentor

Mass disappears by cancellation. No biggie. Or use specific energy

8. Oct 4, 2013

### barryj

So why complicate a simple problem?

9. Oct 4, 2013

### Staff: Mentor

It's no more complicated an approach if you're familiar with the concept. Like I said, different strokes for different folks.

Let's wait to see what the OP comes up with.

10. Oct 4, 2013

### IamBatman

Derive via using other kinematic equations?

11. Oct 4, 2013

### Mandelbroth

Note that this equation is assuming that acceleration, the derivative of velocity with respect to time, is constant. This is, then, just a simple exercise in calculus.

12. Oct 4, 2013

### Staff: Mentor

Hi Marksmeets. Welcome to Physics Forums. We can best answer your question if we know whether you have had calculus yet. Have you?

13. Oct 4, 2013

### IamBatman

I'm thinking if its an intro class then there's no calculus and just want you to use other kinematic equations to this one. I remember having a question where it was just that for intro physics but I can't be certain about op.

14. Oct 4, 2013

### barryj

This is definitely an intro physics question. Only algebra 1 is needed, that is if you have the two kinematic equations.