1. The problem statement, all variables and given/known data A small box is resting on a larger box, which in turn sits on a table. When a horizontal force is applied to the larger box, both boxes accelerate together. The small box does not slip on the larger box. a)Draw a free body diagram of the small box as it accelerates. b)What force causes the small box to accelerate horizontally? c) If the acceleration of the pair of boxes has a magnitude of 2.5 m/s^2, determine the smallest coefficient of friction between the boxes that will prevent slippage. 2. Relevant equations F=ma F=mg F(normal)=-mg F(staticfriction)=(coefficientofstatic)(Fnormal) F(staticfriction)=(coefficientofstatic)(-mg) 3. The attempt at a solution a) http://img233.imageshack.us/img233/109/fstaticti4.jpg [Broken] b) The force applied on the large box c) Find when Fs is equal to Fa So let Fs=Fa Fs=(coefficientofstatic)(-mg) Fa=ma ma=(coefficientofstatic)(-mg) a=(coefficientofstatic)(-g) 2.5m/s^2=(coefficientofstatic)(9.8m/s^2) (coefficientofstatic)=2.5/9.8 (coefficientofstatic)=0.26 Therefore the coefficient of static friction must be 0.26 My friend and I got completely different final answers so I'm wondering if I'm wrong or right. Please help!