How to Calculate Contact Force Between Boxes in Physics?

[papi]

Homework Statement

As shown in Figure 5-19, a force of magnitude 7.50 N pushes three boxes with masses m1 = 1.30 kg, m2 = 3.10 kg, and m3 = 5.80 kg.

Figure 5-19
the figure depicts 3 boxes, in order m1, m2, m3 with a force pushing directly on m1 to the right on a flat level surface.

(a) Find the contact force between boxes 1 and 2.
N
(b) Find the contact force between between boxes 2 and 3.
N

Homework Equations

I know you solve for acceleration by taking the fnet of 7.5 N and dividing it by the total mass to get .735 N.

i then was able to get part b by multiplying a, or .735, by the m3, or 5.8 which was the correct answer. however, when i did the same thing for part one, by multiplying a by m2 to get the contact foirce, i was incorrect. please help and explain

 

[LowlyPion]

Homework Statement

As shown in Figure 5-19, a force of magnitude 7.50 N pushes three boxes with masses m1 = 1.30 kg, m2 = 3.10 kg, and m3 = 5.80 kg.

Figure 5-19
the figure depicts 3 boxes, in order m1, m2, m3 with a force pushing directly on m1 to the right on a flat level surface.

(a) Find the contact force between boxes 1 and 2.
N
(b) Find the contact force between between boxes 2 and 3.
N

Homework Equations

I know you solve for acceleration by taking the fnet of 7.5 N and dividing it by the total mass to get .735 N.

i then was able to get part b by multiplying a, or .735, by the m3, or 5.8 which was the correct answer. however, when i did the same thing for part one, by multiplying a by m2 to get the contact foirce, i was incorrect. please help and explain

The contact force between the blocks will come from the blocks that the force is not yet acting through, that is the blocks that are being pushed.

That means your acceleration applied to the masses it is still pushing ahead of the contact point is the source of your contact force.

In part b) the only mass it is pushing is m3. But in part a) you are pushing both m2 and m3.

 

[thomate1]

The contact force between two objects can be defined as the force that is exerted between the surfaces of the objects in contact. In this case, the force of magnitude 7.50 N is being applied to the first box, causing it to push against the second box, and so on. Therefore, the contact force between any two boxes can be calculated by considering the force applied and the masses of the boxes involved.

For part (a), the contact force between boxes 1 and 2 can be found by taking into account the force of 7.50 N and the masses of the two boxes. Since the force is being applied to box 1, it will experience an acceleration of 7.50 N / (m1 + m2 + m3) = 7.50 N / (1.30 kg + 3.10 kg + 5.80 kg) = 0.735 m/s^2. This acceleration will cause box 1 to push against box 2 with a force equal to its mass multiplied by the acceleration, which is (1.30 kg)(0.735 m/s^2) = 0.9555 N. Therefore, the contact force between boxes 1 and 2 is 0.9555 N.

For part (b), the same process can be applied to find the contact force between boxes 2 and 3. The force of 7.50 N is still being applied to box 1, causing it to push against box 2 and subsequently against box 3. The acceleration experienced by box 2 will be the same as before, 0.735 m/s^2, and this will cause it to push against box 3 with a force of (3.10 kg)(0.735 m/s^2) = 2.2785 N. Therefore, the contact force between boxes 2 and 3 is 2.2785 N.

It is important to note that the contact force between two objects can vary depending on the individual masses and the force being applied. In this problem, the contact force between boxes 1 and 2 is smaller than the contact force between boxes 2 and 3 because the mass of box 2 is larger than the mass of box 1. I hope this explanation helps to clarify the problem and how to approach it.