hey!!!!............here r som
LAWS OF MOTION
1) %age change in wt. in a lift
= + - a/g * 100
2)Tension in pulley
T = 2M1M2g / M1 + M2
3)Pulley system over an inclined plane
T = M1M2 g ( 1 + sin ) / M1 + M2
Pulley system in a lift
T = M1M2 ( 1 + sin $ ) ( g +- a)
Tension in any string = mass draged * F/M
%age change in K.E. (in momentum)
Kf - KO / KO * 100 =( Pf )2 - (Po)2 / ( Po )2 * 100
work done wen.............
1)rod placed horizontally is tilted...............
w = mg(L/2)(sin$)
2)rod placed vertically is tilted
w = mg(L/2)(1 - cos $)
A ball falls frm height "h" and hits the earth inelastically then..............
height of ball after nth collision = e^2n . h
total dist. travelled by ball bfore cmng to rest = h ( 1 + e^2 / 1 - e^@2)
total time taken by ball to com to rest = ( 1 + e / 1 - e). (2H/g)^1/2
The condition that a projectile projected at an angle X with an inclined plane inclined at an angle $ retraces its path is:
(N+1)*Tan$*TanX = 1............
where N is the no. of collisions it makes with the plane...
1)Suppose two particles have position vectors r2 and r1 and their velocities are v2 and v1 (note that r2, r1 , v2, v1 are vectors)..collide is:
r2-r1/ [r2-r1] = v2-v1/[v2-v1]
where [x] denotes magnitude of x.....
2) in the general river- swimmer case....
let Vmg => vel of man w.r.t ground
Vmw=> vel of man w.r.t water
Vwg => vel of water w.r.t ground..
then....the conditions for:
(i) zero drift is: Vwg is perpendicular to Vmg
(ii) minimum time is: Vmw is perpendicular to Vmg
(iii) non-zero min drift is: Vmw is perpendicular to Vmg
the case (iii) arises when vel of man is less than vel of water flw..
Moderation Team
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