S.5 & 6 Newtons Laws Of Motion Caltec S.5

Sponsored by The Science Foundation College 0753 80 27 09 Join Now Newton’s laws of motion First Newton ’s law of motion . A body remains in its state of rest or uniform motion in straight line unless an external force acts on it. This law, also called the principle of inertia. Inertia is reluctance of a body to start moving once at rest or stop moving once in motion. Inertia depends on the mass of the body thus the mass is a measure of inertia. Second Newton’s Law of motion The rate of change of momentum is directly proportional to the magnitude of of the applied f orce producing it and takes place in the reaction of the applied force. Momentum is the product of mass of the body and its velocity. F mV- mU = change in momentum F = But F = kMa, where k is a constant A newt on is a force which gives a mass of 1 kg an acceleration of 1ms-2 F = 1N M = 1kg Sponsored by The Science Foundation College 0753 80 27 09 Join Now A = 1ms -1 1 = k x 1 x 1 k = 1 F = Ma Third Newton’s law of motion For every action, there is an equal and opposite reaction. For example 1 A block of mass 2kg is push ed along a table with constant velocity by force of 5N. Wh en the push is increased to 9N, what is the resultant force and acceleration? Resultant force F 9 - 5  4N But F  ma 4  2a a  2ms -2 Example 2 Two blocks, A of mass 1kg and B of mass 3kg, are side by side and with contact with each other. They are pushed along …