Finding the force required to stop an object

[Nat3]

Homework Statement

An object with mass 6.9*10^-3 kg and velocity 1300 m/s comes to a stop in 1cm. What force was applied to stop it?

Homework Equations

F = ma
v^2=v_o ^2+2a\Delta x

The Attempt at a Solution

v^2=v_o ^2+2a\Delta x
0=(1300)^2+2a(0.001)
a=-\frac{(1300)^2}{2(0.001)}=-8.45*10^8 \frac{m}{s^2}

F=ma
F=(6.9*10^{-3} kg)(-8.45*10^8 \frac{m}{s^2})= -5.83*10^6 N

Apparently that is not the correct answer. What did I do wrong?

Many thanks!

 

[kuruman]

1 cm = 0.01 m not 0.001 m.

 

[Nat3]

Well now, I feel kind of silly :) At least it was a good mistake to make, being so simple to fix!

Thanks!