is newtons 3rd law wrong?

Question

Is newtons 2nd law wrong?

i take a table of mass m and force a block of mass m on it . table breaks out but doesnt the block.where is the rxn force.u cant say there is a mass diff causing it not to work.

Answer 1

Although no theory is "right" Newton is not "wrong" in the sense you probably mean it. As I understand your question (you would do well to apply yourself to learning to write Engish as well as understanding physics), the table provides a reaction force up to its capability and then breaks. The mass placed on the table then falls and the "reaction" is provided in its downward acceleration (F=ma) until it meets the floor after which the floor (hopefully) will provide the reaction needed to restrain the mass from further fall. It is therefore the table and not Newton which is faulted.

Regards,

Bramble.

Answer 2

The mass of the table has nothing to do with this question.

Before the block is put onto the table, I understand the four legs of the table are resting on the floor.

When the block is placed on the table, the table breaks because it is not strong enough to support such a weight.

So, Newton's 2nd and 3rd Laws are NOT violated.

Maybe the legs break, or maybe the table surface breaks, it doesn't matter. All the table is trying to do is to transfer the weight of the block through the table surface and the table legs to the ground.

If the table breaks, it simply means that the table construction is such that the table cannot oppose the weight force of the block. In such a case there is still an equal and opposite force being applied to the block by the table, until the table breaks away.

It is very important to realise that as the block is placed on the table, your hand is providing the force opposing gravity until you release the block. As you release the block onto the table, your hand applies less and less lifting force and the table applies more and more pushing force. At the point where the table breaks, the pushing force from the table suddenly becomes zero, so the block falls through the table.

Answer 3

well... there are many faults with newton's law, but they are still applicable in everyday phenomena.

bout the table, the reaction force on the table caused by the block is more than the breaking force of the table, in other words the table is unable to withstand the force by the block. this example cannot prove that newton third law is wrong, it is not related to the third law.... it is more of the design of the table and the block.

remember the bottom of the legs of the table are the pivot and the block is like a point force acting. using common sense and the principle of moments, of course the table break.

Answer 4

confused cuz u ask if newtons 2nd AND 3rd law are wrong?
for the 3rd law: when you put the block on the table and it breaks that is because the Fn (normal force) of the table on the block doesnt have as great a magnitude as the Fg (force of gravity) acting on the block. since the system isnt in equilibrium the forces between the two objects arent equal. there is an = and opposite reaction from the table on the block but the tables weakness leads it to breaking(the block can handle the table's reaction better). idk if i know all this but what i said it close.

Answer 5

the strenght of the tablr and the block varies
u make a 4 kg weak wooden table and place a 4 kg iron block on it the Non table is beyond a limit it can hold so it brks
Though equal force acts on block but it has more tensile power which is evidentr b/w iron and wood
also even if same material is used the table has less strengh becoz the mass is more distributed while block is compact

3rd law is true for system assuming it can hold the N

Answer 6

After the table breaks, there are still two equal but opposite forces present. One force is the force of gravity attracting the block to the earth, the other is the force of gravity attracting the earth to the blockk! These forces are equal in magnitude but opposite in direction as required by the third law. Note that because the earth is MUCH more massive than the block, the equal force produces a MUCH smaller (immeasurable)acceleration on the earth....

Answer 7

in ur question table mass is M and weight mass is also M (ie. both are same). But u forced the table to brake. that is u have given and extra load to brake the table.
In newtons law "Every action has equal and opposite reaction." when u place a mass in the table force is acting in downward direction (ie gravitational force of earth.) that is equalized by the reactive force of the table. so it is in equilibrium. Now u r forcing the table to brake. thus u r giving an extra force and table can't withhold that. so it is braking. now the extra force given by u is converted as its kinetic energy./ or a heat energy at the contact surface of the table & mass.

Answer 8

the table breaks because it is weak. let me give an example
take two iron blocks of 100kg each and put one over another the iron block at the bottom doesn't break. if the table is very strong it will not break.

Answer 9

No Vishnu, you have it wrong. When you blow air, the action is expelling a certain mass of air, which has a certain energy associated with it. The reaction is a slight force pushing your head in the opposite direction. Of course this force is too small to even notice, but given sensitive enough instrumentation it could be measured. The classic example is a blown up rubber balloon. When you release it, the action is the escape of the trapped air, while the reaction is a force which causes the balloon to fly around the room. Exactly the same principle is responsible for the thrust generated by a jet or rocket engine. The same effect appears whenever a gun is fired, the bullet exits the barrel of the gun with a certain amount of energy, and the same amount of energy is transferred into the gun, which the person firing it senses as recoil. As anyone who has ever fired a high powered rifle or large handgun knows, that can be quite a bit of energy!

Answer 10

Huh?