3.3 Law of Conservation of momentum

From eqn. (6)

Equation (7) is called the Law of conservation of momentum. The total linear momentum of a system on which no external force acts remains conserved, if no external force acts on it.

Solved Problem

1. Find the minimum force with which an object of mass 2 kg should be pressed against a rough vertical wall if the coefficient of static riction between the object and the wall is 0.5. If a force greater than this minimum force is exerted will the object rise up along the wall ? Explain. (g = 9.8 m/s²)

Solution

P : Applied force.

f : Limiting (Maximum) force of static friction.

R : Normal Reaction by the wall on the object.

For Equilibrium, f = Mg & R = P

Index

3.1 Dynamics of a particle
3.2 Dynamics of a system of particles
3.3 Law of Conservation of Momentum

Chapter 4