- #1

Lis277

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## Homework Statement

The power driving the railroad engine is switched off. The engine stops, from its speed of 16m/s^-1, without braking in a distance of 1.1km. A student hypothesis that the horizontal resistive force is constant. Based on the hypothesis, calculate the mass of the railway engine.

## Homework Equations

Teacher didn't provide any relevant equations but i assume F=ma and vf^2-vi^2=2ad are important

## The Attempt at a Solution

__First i tried to find__

acceleration

acceleration

vf^2-vi^2=2ad

vf=0

vi=16

a=?

d=1.1

(0)^2-(16)^2=2(1.1)a

-256=2.2a

-116.36=a

I think the next step would be to find net force to plug all my variables into F=ma to find mass. I know net force is the total force on an object but I'm not sure how to find net force from my given variables.