# Calculate the maximum force required to accelerate the box

1. Jan 12, 2012

### charch

1. The problem statement, all variables and given/known data
Calculate the maximum force required to accelerate the box from rest and not move the glass on it's surface on top of the box. I am given the mass of the box and glass, and both the static and kinetic coefficients of both objects. I have to create a spreadsheet that can accept any number that is inputted

2. Relevant equations
Ff=umg, fnet=Fg+Fn+Ff+Fa

3. The attempt at a solution

so far ive got the maximum force of static friction for the glass, using the equation F=umg... Im unsure how the box beneath it affects the force applied to the glass

Last edited: Jan 12, 2012
2. Jan 12, 2012

### Spinnor

Re: Friction

The maximum force will give you the maximum acceleration, a. The required force must accelerate both masses with acceleration a and oppose the friction force on the box (don't forget the mass of the glass increases the friction force).

Hope this helps.

3. Jan 12, 2012

### SammyS

Staff Emeritus
Re: Friction

Hello charch. Welcome to PF !

Draw two free body diagrams; one for the box, one for the glass.