# Physics A123 Acceleration problem

## Homework Statement

Excellant human jumpers can leap strait up to a height of 130cm off the ground. To reach this height, with what speed would a person need to leave the ground?

## Homework Equations

I would just like to know what equation I would need to solve this,

## The Attempt at a Solution

xf = xi +(vx) (delta)t + 1/2ax(deltat)^2

PhanthomJay
Homework Helper
Gold Member
Since the equation you list has 2 unknowns , vx and t (a is known), you can't solve it without another equation. Why not instead try another equation that has just one unknown, vx (the initial velocity)? You must first note what is the the final velocity at the top of the jump, and what is the acceleration?

you can use this eqn

v^2 - u^2 = 2as

Last edited:
hmmmm, yeah this is all the iformation its giving me, I'm trying to find the (Vx)f, the final velocity of this person. if i'm not mistaken this equation would look like a parabola, right?

ya see i'm a first time physics student ya know...and generally I can teach myself a a subject, haha but physics it not just any other subject...its like the king of all science subjects

why 2 unknowns?
my eqn gives you the answer ... can't write the answer ... got warnings for writing answers ....

what do you think v(final) would be?