AP Physics 1

vectors are in the form _____

_i + _j

i in a vector is

horizontal

j in a vector is

vertical

when adding, subtracting, or multiplying vectors make sure you

do it to each individual component. ALSO pay attention to the direction of the vectors too (because negatives matter)

to get the direction of a vector

use tan-1 ( ) to get the degrees (can be clockwise or counterclockwise)

average velocity is

displacement over time

acceleration is 0 only when

the velocity is constant, NOT speed

at the end of a projectile motion, remember that the resultant speed is equal to

the Pythagorean theorem for BOTH components

always remember that speed is the ____ of velocity

magnitude

newtons first law is

the law of inertia

newtons second law is

Net force = ma

newtons third law is

equal and opposite reactions

what are action reaction pairs? (3rd law)

action reaction pairs always happen on 2 _____ objects

DIFFERENT

equal and opposite forces do _____ act on the same object

NOT

even if the speed of an object in circular motion is constant, the velocity

is not constant because its always changing directions!

acceleration centripetal and force centripetal formulas

ac = v²/r Fc = mv²/r

can a force centripetal do work?

NO! its motion is always perpendicular to the force

other than tension, what other forces can provide centripetal forces?

GRAVITATIONAL (what keeps a planet in orbit) and FRICTION (what allows cars and people to turn, imagine trying to turn in a circle in a car on frictionless ice)

The centripetal force is the force required to

keep an object in circular motion. if the force is too high it wont be able to move in a circle

remember that one revolution per second means

velocity = 2(pi)r

when calculating work the force and distance

must be parallel! they can be opposite too

work is negative when

the force is opposite of the motion

if there is a force on an object pulling it up the force normal can be

the force normal can be reduced

if force isn’t constant then the work is equal to

the area under a Force vs Displacement graph or the integral of the force function

total work is equal to

change in Kinetic energy, or final ke - initial ke

work done by gravity is equal to

-(final potential energy - initial potential energy)

if no nonconservative forces (like friction) are acting then the energy

is conserved by the law of conservation of energy

if a nonconservative force is present then how does the mechanical energy formula change

KE initial + U initial + Work of Nonconservative force = KE final + U final

please know that there is a HUGE difference when they ask for displacement or _____

distance!!!!!! area under the curve is much different

what is momentum equal to

p = mv

what is force equal to (momentum)

F = (change in momentum) / (change in time)

what is impulse equal to

change in momentum

when is momentum conserved? (law of conservation of momentum)

when there are no external forces acting on the system (such as friction or air resistance)

what is distance equal to?

velocity times time

elastic vs inelastic collision

elastic is when they bounce off in opposite directions, and inelastic is when they move in the same direction after they collide

when is a collision perfectly inelastic?

when the final velocity of both objects are the same

when is kinetic energy NOT conserved in collisions

when its an INELASTIC collision, and even less is conserved in a perfectly inelastic one

why is direction so important to remember in momentum problems???

because it can make the momentum turn NEGATIVE or POSITIVE