Physics help please determining distance of box pushed

[lbella026]

Homework Statement

A block has a mass of 20kg is at rest on the floor. This block is then pushed by a horizontal force of 8N across the floor. The final speed is 2 m/s. Determine the distance the box was pushed.

Homework Equations

Fnet=ma
d=(t)(s)
a=(chand in velocity)/(change in time)

The Attempt at a Solution

Using all three equations I found the distance to be 10m. But this answer is incorrect. I can't figure out what I am doing wrong.

 

[pgardn]

Homework Statement

A block has a mass of 20kg is at rest on the floor. This block is then pushed by a horizontal force of 8N across the floor. The final speed is 2 m/s. Determine the distance the box was pushed.

Homework Equations

Fnet=ma
d=(t)(s)
a=(chand in velocity)/(change in time)

The Attempt at a Solution

Using all three equations I found the distance to be 10m. But this answer is incorrect. I can't figure out what I am doing wrong.

have you used the kinematic equation Vf^2 - Vo^2 = 2*a*displacement ?

I think you figured out acceleration a, properly...(assume we have a frictionless surface). So if you know a, Vf and Vo, you can figure out displacement (or distance the box moved).