- #1

Cole07

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## Homework Statement

A Lufthansa A320 accelerates from rest to lift-off speed of 72.99 m/s in 25.00 s. Each of the plane's two jet engines provides a forward force (thrust) of 103.00 kN. What is the mass of the plane?

How far does it travel down the runway before lift-off?

**2. Governing equations**

Vf=Vi+at

EF=ma

D=Vit+at^2

## The Attempt at a Solution

Vf=72.99

Vi=0

a=?

t=25.00s

I used Vf=Vi+at to get a=2.9196

then EF=ma to solve for mass and got 35.27880532 which i was told was wrong i went back and looked at the problem and thought that since the plane has two engines i would double the mass, but it was still wrong. and i tried D=Vit+at^2 for the second problem, but it didn't work either i don't understand what I'm doing wrong. any help would be appreciated

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