Alevel physics Flashcards
(78 cards)
free fall in air.
at time 0, only weight is acting, acceleration is g, then speed increases, so drag increase, so resultant decrease, so decreasing acceleration, then drag is equal weight, fr is 0. reaching terminal velocity, then. drag greater than weight, deceleration
describe x axis motion in projectiles
no force, only weight, constant horizontal motion, speed is distance over time
describe y axis
constant acceleration, y component changes, use 5 acc rules, up positive, down negative
what is rule of force
mass. times acceleration
when is a body equilibrium
resultant force AND resultan moment is 0
what is inertia
the tendency of object to reset change in state of rest or uniform motion
what is mass
measure of inertia// amount of matter in body
what is first law
object remains equilibrium unless a resultant force is acting on it
newtons second law
force is the rate of change in momentum
newtons third law
when 2 objects interact, for every action thee is an equal and opposite reaction
what is momentum
mass times velocity
impulse
mv-mu, or ft
why use softer material\l in crashing
time increases to crash so force decrease so safer
law of. conservation of momentum
before equal after, m1u1 and m2u2 is equal to m1v1 plus m2v2
what do to with 2d collision.
each axis separately then simultaneous
what’s the check for elastic collision
u1-u2=v2-v1
types of forces
tension, friction, drag, upthrust, weight, normal contact
proof of conservation of momentum
force is rate of. change in momentum, when time is same, momentum. before. collision is ewualnbut opposite to collision after
whats center of gravity
point where whole body is considered to act.
whats moment
force times perpendicular distance
when is max moment?
when. angle is 90 DEGREE
whats a couple
2 forces equal and opposite act. on 2 different points. causing object to rotate
pressure
force/ area or ugh
total pressure?
atm 100000 plus pgh
