Question
Question: Explain the activity to observe action and reaction acting on two different objects....
Explain the activity to observe action and reaction acting on two different objects.
Solution
Newton’s 3rd Law states that for every action there is an equal and opposite reaction. These action- reaction forces act in a straight line. The reaction force is seen as an opposition force by object 2 on object 1. Action-reaction are universally present as pairs, as they’re interaction (or contact) forces.
Complete answer:
In the question, they’ve asked for action and reaction acting on two different objects.
Let us consider rocket propulsion. The thrust due to the hot gases produced by combustion of fuels, which is the action, leads to the propulsion of the rocket, in the forward direction which is the reaction.
Here, the two objects involved are the hot gases and the second object is the rocket itself.
Newton’s 3rd law states that- “For every action there is an equal and opposite reaction”. There’s a little ambiguity here in Newton’s third law. So, let us put it in another way which is more elaborate and has the same meaning.
“Forces always occur in pairs. If object 1 exerts a force F on object 2, then object 2 exerts an equal and opposite force –F on object 1, simultaneously in a straight line.” i.e.,
F12=−F21
Where:
F12 is force applied by object 1 on object 2
F21 is the force applied by the object 2 on object 1
‘−‘ indicates the opposition or the opposite direction of F21.
In our example, F12 is the force (or thrust) applied by release of hot gases on the rocket and F21 is the force applied by the rocket on the hot gases.
Note:
According to Newton's third law there’s always involvement of two objects. The forces like tension and recoil force are the direct consequences of Newton’s third law.
Sometimes, one may be mistaken that the action - reaction forces might cancel each other out as they’re equal and opposite. It is not the case, because the forces are on two different objects.