Summary Topic 6: Further Mechanics notes

Impulse
force(N ) or
change in momentum ( Kgms ) "




s F- Pfinal p -




before
¥ =¥-change in time G)

change in momentum
lkgms'S Force is the rate of change of
momentum on a body
Impulse is equal to the change in momentum
change
*gmgh1 may Force must be constant
[ =f f- , *

p murmur
-

-




impulse fire ↳ timely *
Impulse is the direction the force
ftp.af.yelocityinuitjify
in same as
( Ns)
CM5Y


Small force acting over a
long time has the same effect as a
large force acting over a short time



Applying Conservation of linear Momentum
9




Total momentum before total momentum after = * Momentum is a voter
(providing no external force acts )


conservation of linear momentum in 2D
*
Always conserved


* Each component of momentum is conserved separately (resolved)
sum of horizontal components will be equal before and after a collision
sum of vertical components will be equal before and after a collision

anp_k_
A red snooker ball travelling at 25ms collides with a
"


green
snooker ball which ,
is at rest
Both snooker balls have the same mass m

The angle of collision is such that the red ball moves off at 28 below the horizontal at 18ms
"




and the green ball moves off at 55 above the horizontal with speed
,
v as
,
shown

BEFORE Pimvn horizontal momentum before = horizontal momentum after
m
M '



2.5mg
+ 09 UC05 55
Mllred +0 =
Mummy MVh(greens =




AFTER M12 5) to =
mfrcos 55 ) + makes 289 V =
0.90555
"
25 =
UO55 -118cos 28 U = 16ms
T
25 =
vcos55.tl 6
-28

18m51
✓