LAW OF MOTION

LAW OF MOTION :-

       Momentum is defined as product of mass of its velocity p=mv , unit=Kgm/sec(2)

@ newton first law of motion:-

           every body constitude in its state of rest of uniform motion unless its is compel by some external force to change that state

i) First law of motion in inertia :-

           inertia is  a property of body by virtue of which the body tries to remain in its existing in stste of rest of uniform motion into independent upon mass of body

ii) second law :-

         ratio of change of momentum is directly proportional and take plain the direction of applied force

# Drive :-

           let a body of mass 'm' changes its velocity 'u' to 'v' in time 't'. when a force of act on it now initial momentum of the body = mu
final = mv
the rate of change of moment = mv-mu/t
m(v-u)/t and if v-u=at
m(at)/t             =ma
but from newton second law motion states rate of change of moment is directly proportinal to applied force
'F' is directly proportional to m ><a
F=K ma
K=1, if k=1 then
F=ma

iii) Third law :-

        it state that to every action there are eqaul and opposite reaction

@ Laws of conservation of momentum :-

        it state that if the resulatnt of all the external forces acting on the system is zero. the momentum of the system remain constant of initial moment of the system is equal to final moment of the system

@ recoiling of gun :-

        when the bullet is fired from a gun the opposite reaction of the built of the gun is known as recoiling of gun

@ Before the gun fire both the bullet and gun are at rest :-

            initial moment of the system =0
let, m = mass of the bullet
M= mass of gun
v = velocity of the bullet after firing
V= velocity of gun after firing
Final momentum after firing = MV-mv
initial p= final p
0 = mv - MV
V= -mv/M

@ Impulse :-

        defined as impulsive force >< time = F ><t
=> m (v-u)/t >< t
=> Mv -mu , change in momentum

@ analysis of motion of lift :-

            lift are we use to move heavy loads up or down
let, W= weight carried by lift
m= Mass carried by lift = w/g
a = uniform acceleration of lift
T= tension in the cable

# when lift moves upward :-

   net force in upward direction
T-w --------- (i)
but net force = ma
                  = w/g >< a -----------(ii)
T-W = w/g >< a
T= W +w/g >< a
T= W (1+a/g)
T= mg (g+a/g)
T= M(g+a)