# Friction and Normal Force

## Homework Statement

A pizza box thrown across the room strikes
the floor with a horizontal velocity of 2.0 m/s.

## Homework Equations

If the 300-g box encounters a floor with a
coefficient of kinetic friction of 0.3, how far
will the box slide before coming to rest?

## The Attempt at a Solution

So I did it by using the equation a=ug(u is coefficient of kinetic friction), and I got -2.94 m/s^2 as the acceleration. Then, I used a kinematics equation and found d to be 0.68 m, but the answer says its 0.068 m. Is the answer at the back wrong?

Also, I was wondering if the given 300g mass of the box was needed in the solution?

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PeterO
Homework Helper

## Homework Statement

A pizza box thrown across the room strikes
the floor with a horizontal velocity of 2.0 m/s.

## Homework Equations

If the 300-g box encounters a floor with a
coefficient of kinetic friction of 0.3, how far
will the box slide before coming to rest?

## The Attempt at a Solution

So I did it by using the equation a=ug(u is coefficient of kinetic friction), and I got -2.94 m/s^2 as the acceleration. Then, I used a kinematics equation and found d to be 0.68 m, but the answer says its 0.068 m. Is the answer at the back wrong?

Also, I was wondering if the given 300g mass of the box was needed in the solution?
I like your answer, and you don't need the mass - unless you are unaware of the a = μg arrangement and want to do it from first principles..