Can you help me? I'm solving in action and reaction force problem.?

Question

"Two blocks are on a frictionless, level surface. They are in contact, but are not connected. Block 1 is on the left, and has a mass of 6.6 kg; block 2 has a mass of 4.2 kg. A constant force of 27 N is applied to block 1, parallel to the level surface. What is the magnitude of the force that block 1 exerts on block 2?" I solved first it's acceleration which is 4.09 m/s^2. Then I solved the Force, F=ma, F=(6.7kg)(4.09m/s^2)=27N. So the magnitude is 27. What did I make mistake? the answer says incorrect. Can anybody know this? please explain to me. Thanks.

Answer 1

Though both masses are not connected, they are in contact.

The external force F is applied on the combined mass of ( m1 + m2)

Therefore, both move with the same acceleration [a] given by the equation

F = (m1 + m2) a

Find [a} from the given data.

Now to find the forces acting on m1 and m2,

Again think of the equation

F = (m1 + m2) a

This can be written as

F = m1 a + m2 a.

If we write m1a as f1 and m2 a as f2 the equation becomes

F = f1 + f2.

f1 is the force acting on m1. f1 = m1 a

f2 is the force acting of m2. f2 = m2a.
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Now using the given data

a = 27 / [6.6 + 4.2] = 2.5 m/s^2.

The force acting on f2 = m2 a = 4.2 x 2.5 = 10.5 N

The force acting on f1 = m1 a = 6.6 x 2.5 = 16.5 N.
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By checking the results you get more understanding of the formulae used.

The sum of the forces 10.5 N and 16.5 N is 27 N.

Acceleration of m1 = Force / mass = 16.5 / 6.6 = 2.5 m/s^2

Acceleration of m2 = Force / mass = 10.5 / 4.2 = 2.5 m/s^2

Note that the acceleration is common for both the object.
a = f1/m1 = f2/m2.

Answer 2

You needed to find the acceleration by dividing the force on block 1 by the total mass.

a=(27 N)/(6.6 kg + 4.2 kg) = 2.5 m/s^2.

Both blocks will accelerate at that rate.

Then to find the force on the second block just multiply this acceleration by its mass.

F=(2.5 m/s^2)*(4.2 kg) = 10.5 N.

Answer 3

a. Is unsuitable because the opposing drive happens even as and that's an motion no longer a drive despite the fact that forces are related to it. b. Is unsuitable as gravity acts upon the ball normally irrespective of the motion of spiking the ball. Remember gravity isn't a Force it's the reason of the drive tremendous false impression as a way to reason disorders later if you aren't getting correct. c. Is the proper reply it complies with Newtons legislation. You must appear those legislation up and be taught them they're primary in knowledge Force and movement. A powerful appreciation of those legislation will make even probably the most difficult of approaches comprehensible.

Answer 4

F= (m1 + m2) x a
You'll also add the mass of 2nd block to the first block.

Answer 5

a = 27/(6.6 + 4.2) = 27/10.8 = 2.5 m/s^2
F = 4.2*2.5 = 10.5 N