(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Blocks A and B are sitting side by side (touching) on a horizontal surface. A constant horizontal force Fa is applied to block A, which pushes against block B with a 32.0 N force directed horizontally to the right. The same force Fa is applied to block B; now block A pushes on block B with a 16.0 N force directed horizontally to the left. The blocks have a combined mass of 30.0 kg.

(a) What is the magnitude of the acceleration of the blocks in figure (a)?

(b) What is the magnitude of the force Fa?

2. Relevant equations

Fnet = ma

3. The attempt at a solution

Part 1: Fa pushes on block A:

Block A has Fa pushing to the right, and block B pushing to the left so

Fnet = massblockA *acceleration = Fa - 32N

Block B pushes back on block A (only horizontal force on it)

Fnet = massblockB *acceleraton = 32N

mass blockA + massblockB = 30kg

Using these three equations I solved for Fa and got that Fa = 30kg*acceleration...

I thought that I could use the next set of data (Fa pushing on block B) to come up with another equation, then I could solve for Fa and acceleration, but the equations are exactly the same, so pretty useless.

Any help would be great, thanks!

(ps~ I sometimes have trouble with FBDs, so if something is wrong with how I laid out the forces, it would be great to know!)

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# Fnet = ma problem

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