newtons laws of motion
- types of forces
- contact forces -applied on contact e.g. tension
- field forces-applide from a distance e.g. gravity
- 1st law (law of inertia)-a body continues to be in aa state of rest or uniform motion until and unless an external force is applied
- force acc to newtons 1st law - force is a quantity which can change the state of motion of a body
- inertia - tendency of a body to retain its state of motion
- momentem = mass x velocity
- 2nd law - rate of change of lenier momentem is directly proportional to the force applied on it and is in the direction of the force
- 3rd law every action has an equal and opp reaction
- impulse = instantanious change in momentem
- eqilibrium = total force on a body in any direction = nil
- friction = coeffecient of friction x normal reaction
- banking of roads = slight slope on roads which is lower on the side of turn
- anglr of repose=angle at which all bodies start sliding irrespective of their mass
- purpose of banking =
- to reduce frictional wear of tyres
- avoid skidding
- avoid overturning
- p.s. next lecture tommorrow work power and energy
motion in one dimenton
- motion in one dimension - particle moves along a straight line.
- sign convention -1.towards right= +ve 2.towards left = -ve
- uniform velocity - body covers equal displacement in equal amounts of time.
- variable velocity - body covers unequal displacement in equal amounts of time.
- average velocity = total displacement / total time.
- accelerated motion - velocity changes with time
- uniform acceleration- equal change in velocity in equal amounts of time
- variable accelration-unequal change in velocity in equal amounts of time
- av. velocity in accelrated motion =final vel - initial vel./
- eq. of motion =>
- 1 v = u+a
- s=ut+14/2at
- v squared + u squared =2as
- p.s.-same method can be used to solve questions related to motion in 2 and 3 dimensions by applying the above equations in x y and z direction
- p.s.s. next post newtons laws of motion
