- #1

mitchy16

- 23

- 2

## Homework Statement

On a horizontal frictionless floor, a worker of weight 0.900 kN pushes horizontally with a force of 0.200 kN on a box weighing 1.80 kN. As a result of this push, which statement could be true?

A ) The box will not move because the push is less than its weight.

B ) The worker will accelerate at 2.17 m/s2 and the box will accelerate at 1.08 m/s2, but in opposite directions.

C ) The worker and box will both have an acceleration of 2.17 m/s2, but in opposite directions.

D ) The worker and box will both have an acceleration of 1.08 m/s2, but in opposite directions.

E ) The worker will accelerate at 1.08 m/s2 and the box will accelerate at 2.17 m/s2, but in opposite directions.

## Homework Equations

F=ma

F

_{A on B}= -F

_{B on A}

## The Attempt at a Solution

(converted all kN to N first)

Solving for mass:

WORKER:

w = mg

900N = m(9.8m/s

^{2})

91.836 kg = m

BOX:

w = mg

1800N = m(9.8m/s

^{2})

183.67 = m

Solving for acceleration:

WORKER:

F=ma

200 = (91.836)(a)

2.17 = a

BOX:

F=ma

-200=(183.67)(a)

-1.08 = a

I got the answer B, which is correct but why is it correct? I did all the work and got it, but why is it not A? Is it because Newton's third law? Sorry, just don't understand why this is correct.