Momentum

• Momentum is the product of the mass and velocity of an object. It is given by the formula: momentum = mass x velocity (p = mv). The unit of momentum is Kgms^-1 but can also be expressed as N s. This results in momentum being a vector quantity because velocity is a vector quantity
• The principle of conservation of linear momentum states that in any interaction between bodies, linear momentum is conserved, provided that no resultant external force acts on the bodies
• There is a link between Newton's second law of motion and its momentum. This is through the equation acceleration = change in velocity/change in time. Then you can write the second law as F = mass x change in velocity/ change in time. Or F = change in momentum/change in time. This is known by the equation resultant force = change in momentum/time interval
• Newton's second law of motion states that the resultant force exerted on a body is directly proportional to the rate of change of linear momentum of the body
• Newton's second law can be rearranged to F△t = △(mv). The product F△t is called the impulse of the force and has the unit N s. The equation shows that this is equal to the change in momentum of a mass when it is subjected to a resultant force
• Impulse can be given by the formula: impulse = force x time, which is equalled to the change in momentum. So, an impulse = change in momentum
• The impulsive force is when the forces can be very large and the time during which they act is very small. The area of the strip represents the impulse, Ft during an instant t. The area under the curve equals the sum of all the strips, which is the same as the total change in momentum of the ball. The average force can be estimated using the impulse-momentum equation F△t = m△v. If the time of contact is known and the change in momentum is measured.

  
• The product of a body's mass and velocity is useful in analysing such collisions: this product is called the body's momentum, or its linear momentum
• If momentum is conserved in a collision, momentum A = momentum B. So, mAvA = m(A + B) VB
• The importance of momentum was first realised by Sir Isaac Newton. Newton established the basic principles which link force and motion. He stated these basic principles in three laws, known as Newton's laws of motion