ABSTRACT
Newton’s first law of motion states: a body continues in a state of rest or in a state of uniform motion in a straight line unless acted on by some external force
Hence the momentum of a body remains the same provided no external forces act on it The principle of conservation of momentum for a closed system (i.e. one on which no external forces act) may be stated as:
the total linear momentum of a system is a constant
At the end of this chapter you should be able to:
• define momentum and state its unit • state Newton’s first law of motion • calculate momentum given mass and velocity • state Newton’s second law of motion • define impulse and appreciate when impulsive forces occur • state Newton’s third law of motion • calculate impulse and impulsive force • use the equation of motion v2 = u2 + 2as in calculations
The momentum of a body is defined as the product of its mass and its velocity, i.e.
