How Does Friction Affect the Reaction Force Between Two Blocks?

[Epshita]

Homework Statement

There are two blocks against a wall on a frictionless table. I can't really manage a diagram, so please imagine this. There are two blocks, one of 5 kg and another of 10 kg, against each other. The 10 kg one is touching the wall.

The frictional coefficient between the two blocks is 0.2

A force of 200 N is applied to the 5 kg block. What is the reactional force?

Homework Equations

Newton's laws and Frictional force = frictional coef. x Normal

The Attempt at a Solution

Should it not be 200 N back? ( The ans. is 177) What role does the friction play here?

 

[haruspex]

which direction does the 100N force act in?
Static or kinetic friction?
Any friction between block and wall?

 

[Epshita]

200 N force acts towards the wall. Static friction. No friction between block and wall.

 

[haruspex]

200 N force acts towards the wall. Static friction. No friction between block and wall.

And perpendicular to the wall? If so, I agree the reaction should be 200N. I strongly suspect you have not described the problem correctly.
Have you posted the statement of the problem exactly, word for word?
If there is an accompanying diagram, why can't you post it? Do you need a scanner?

 

[HalfLostAndSearching]

I can confirm that the reactional force on the 5 kg block will indeed be 200 N, as per Newton's Third Law of Motion which states that for every action, there is an equal and opposite reaction. Therefore, the force applied on the 5 kg block will result in a reactional force of 200 N in the opposite direction.

In terms of the role of friction, it will play a part in determining the net force on the 5 kg block. Frictional force is calculated by multiplying the frictional coefficient by the normal force, which in this case would be the weight of the 5 kg block. This frictional force will act in the opposite direction of the applied force, reducing the net force on the block and resulting in a slightly lower reactional force of 177 N. This is due to the fact that the 10 kg block is also exerting a normal force on the 5 kg block, reducing the overall normal force and therefore the frictional force.

In conclusion, the reactional force on the 5 kg block will be 200 N, but the presence of friction will slightly reduce the net force and therefore the resulting reactional force.