mechanics pt2 Flashcards
in any question about newtons first law always say
0 acceleration
when talking about energy changes and want to say friction say
THERMAL ENERGY due to friction
4 marker terminal velocity always say
- accelerating at start / speed increasing
- then apply newtons 1st law = no acceleration at RF=0N
direction resultant force in triangle is angle between
vertical and resultant - so tan changes
work done by cyclist is
energy into system (don’t be put off by work done)
2 things required for equilibrium
force balanced and moments balanced
what causes acceleration on a ramp
component weight parallel to slope - therefore if on flat land 0 acceleration
where is acceleration greatest on ramp with decreasing gradient
at top
when talking about change in momentum
-initial
-horizontal change or vertical change
-
for rain water falling vertically then caught by truck how does momentum change
- initial no horizontal m
- gains horizontal m but loses vertical m
centre of mass IS NOT _ BUT IS
where mass appear to act IT IS WHERE WEIGHT APPEARS TO ACT - MASS NOT A FORCE SO CANNOT ACT
centre of mass is directly below point of suspension so that
moments balance and there is no turning effect about point (pivot)
why centre of mass vertically below suspension if in equilibrium
- Point suspension = pivot
- no resultant moment about point of suspension
uniform metre ruler assume length =
100cm
in elastic collision forces on each Masses are
equal (same for all forces newtons third law)
