Force exerted on block B by Block A when being pushed on a frictionless surface

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The force exerted by Block A on Block B is calculated using the formula mB * a, as Block B's mass directly influences the force required to keep it accelerating with Block A. If Block B were absent, Block A would not exert any force on that side, indicating that Block B's inertia is crucial for the interaction. The mass of Block B determines the magnitude of the force due to its inertia. In analyzing such problems, drawing free body diagrams for each block is essential to visualize the forces acting on them. Understanding these principles clarifies the dynamics between the two blocks on a frictionless surface.
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Homework Statement
Boxes A and B are in contact on a horizontal, frictionless surface (Figure 1). Box A has mass 25.0 kg and box B has mass 7.0 kg . A horizontal force of 100 N is exerted on box A \.
Relevant Equations
F = ma
I was just wondering why you would do
mB * a
to get the force A is exerting on B instead of
mA * a

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If B were not there, would there be any force on that side of A? If B was super small, would it take much force to keep it accelerating along with A? What if it was very large? So, you see, B’s inertia is the reason there is any force between B and A and B’s mass is what you need to figure out how big the force is.
 
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In problems like this always draw the free body diagrams and show the forces on each block separately. Then you can write the equations and they should makes sense.
 
yashboi123 said:
why you would do
mB * a
to get the force A is exerting on B instead of
mA * a
Because A's acceleration is a consequence of the two forces on A, whereas there is only one force on B.
 
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