QS Study

Application/Uses of Newton’s Laws of Motion

When a body applies force on another body then the second body also applies equal and opposite force on the first body. We have learnt about this action and reaction forces from Newton’s third law of motion. In nature forces act in couples. In nature there is not individual separate force. Two forces are complementary to each other. One of these forces is called action force and the other one is reaction force. As long as action force is there, there exists reaction force also. Practical application of Newton’s laws of motion are described below with example.

Pulling a boat by rope (Towing a boat):

Suppose M is a boat. At point O a rope is fastened and the boat is pulled by the rope along the bank of the river OR with a force F. F can be resolved at point O into two components— horizontal and vertical components [Figure].

Horizontal component = F Cos θ, its direction is along OA and the vertical component = F Sin θ, its direction is along OB.

Horizontal component of the force F Cos θ pulls the boat forward and the vertical component F Sin θ pulls the boat towards the bank of the river. But vertical component F sin θ balanced by the helm. Larger the rope of the boat, smaller is the angle θ. consequently value of F sin θ will be less and that of F cos θ will be more. So, the boat will move fast ahead.