I'm A Beginner Need help -9th Grade Physics-

[1mai28]

1. Homework Statement :

A dragster accelerates from rest at 49 m/s^2. How fast is it going when it has traveled 325 m?



I'm a complete beginner, I'm not really sure how to even approach this problem so please, with each step taken, provide a VERY detailed explanation of why and how you did this step! I'm so confused!

 

[SHISHKABOB]

we can't actually take you step by step through the problem here, but can try to help along the way

do you have any formulas regarding constant acceleration?

 

[howie8594]

There is one kinematics equation that has everything you need to solve for final velocity.

 

[1mai28]

Well so far, the formulas I've learned are:

v= Δx/t
a= Δv/t
Xf= X0 + V0t
Xf = X0 + V0t + 1/2at^2
Vf = V0 + at
Vf^2 = V0^2 + 2aΔx

 

[SHISHKABOB]

so if you look at those formulas and look at the information you've been given, and then look at what you need to find

which formula should you use

 

[1mai28]

Umm, well the question is asking how fast it is going...

So I would have to use

Vf = V0 + at
or
Vf^2 = V0^2 + 2aΔx?

Or does it not matter which one I use?

 

[SHISHKABOB]

you aren't given anything about the time, so the first one is not going to be useful

so how would you use the equation you've chosen?

 

[1mai28]

"A dragster accelerates from rest at 49 m/s^2. How fast is it going when it has traveled 325 m?"

So, Vf^2 = V0^2 + 2aΔx

I guess
a=49 m/s^2
Δx would be 325?
And its at rest? Would V0^2 be equal to 0 then?

So then,

Vf^2 = 0 + 2(49)Δ(325)?

 

[SHISHKABOB]

yes :)

the key to these problems is listing what you know and what you don't know

then find the formula best suited for what you've got

 

[1mai28]

So

Vf^2 = 31850?

Vf = 178.47?

 

[SHISHKABOB]

looks good to me

 

[1mai28]

Thanks! :D