Force two blocks, physics help!?

Question

A force F of 12 acts on two blocks on a frictionless surface.

------Force---------->box A(3.0kg) box B(2.0kg)

What is the acceleration of the system? m/s^2
What is the magnitude of the force that block A exerts on block B?N
What is the magnitude of the force that block B exerts on block A?N

step by step plz helps understand better:}

Answer 1

As the force of 12 N is an external force, you can treat the two boxes as one huge 5.0 kg mass. Solve F=ma for a, and you have an acceleration of 2.4 m/s^2.



Then you can draw free-body diagrams of each box and do force balances. The whole system has one acceleration. With box A, my equation was ma= 12N-F, where I was solving for F. F (exerted by box B) came out to 4.8 N.



By means of Newton's 3rd law, box A exerts a 4.8 N force on box B. Or, you could multiply box B's mass (2.0 kg) by acceleration (2.4 m/s^2) to get 4.8 N.

Answer 2

acceleration = sum of forces / mass total

force = mass x acceleration



should be able to solve using that information.

Answer 3

you're close, you purely have A and B swapped. whilst the exterior stress pulls on block A, which attracts on the string, which attracts on block B, the stress interior the string is the only stress appearing on block B and for this reason equals mB * a.