- #1

Alyona

- 7

- 0

## Homework Statement

A person is pushing a box. The net external force on the 60 kg box is stated to be 90 N. If the force of friction opposing the motion is 30 N, what is the acceleration of the box?

## Homework Equations

This seems to be a pretty easy, straightforward problem, but I'm confused. Is the first or second solution correct?

## The Attempt at a Solution

Fnet = F - f = ma

90 N = F - 30 N = (60 kg)a

a = 90 N / 60 kg = 1.5 m/s2

Fnet= F - f = ma

90 N = F - 30 N

F = 120 N

F = ma

120 N = (60 kg)a

a = 120 N / 60 kg = 2.0 m/s2