physics midterm

Newton’s laws

1. an object in motion remains in motion and an object at rest remains at rest

2. force = mass x acceleration

3. every action has an equal and opposite reaction

scientific method

observe, question, research, hypothesize, experiment, test hypothesis, conclude, report

scalar

quantity with only magnitude

vector

quantity with both direction and magnitude

speed

scalar, magnitude of object’s rate of change

velocity

vector, direction and magnitude of object’s rate of change

field force

force exerted without direct contact, ex: gravity

contact force

force exerted on an object by another, ex: push/pull

weight formula

mg

weight unit

N down

mass formula

weight/g

mass unit

kg

apparent mass

mass never actually changes from different gravitational pulls, but it appears that it does

weight

the gravitational force experienced by an object

tension

specific type of force exerted by a rope or string, symbolized by F of T, mass of object is negligible (ignore it), will sometimes take place of normal force (if straight hanging)

F of T = mg N up

if object hanging on a stationary rope tension will be the weight of the object (same equation as finding weight)

F of T = mg +/- ma N up

if object on an accelerating rope (if up you add, if down you subtract) the rope's tension will change

F of T = 0

if rope is moving faster than free fall

m = F of T / g +/- a

mass equation

greater normal force

if pushing down on an object on a surface because needs to work against F of g and F of p

F of g = mg

weight equation

smaller normal force

on an inclined plane (F of g is bigger than F of N)

mole

amount of a substance

meter

length/distance

second

time

kelvin

temperature

kilogram

mass

candela

luminous intensity

amp

electric current

newton

force

ohm

electric resistance

meter per second

velocity

negative exponent

when representing a small number in scientific notation ten to the power of what

positive exponent

when representing a large number in scientific notation ten to the power of what

leading zeros

not significant (because when changed to scientific notation)

final zeros after decimal

significant

non-zero digits

significant

zeros between non-zeros

significant

counting/definition

infinite number of significant digits (as long as amount is correct)

final zeros

not significant (best to not include final zeros not after decimal point)

power of ten

not significant

decimal left

when going to left of metric staircase (giga, mega, kilo, hecto, deca) or divide by ten each step

decimal right

when going to right of metric staircase (deci, centi, milli) or multiply by ten each step

Acceleration

type of motion, change in velocity over time (speeding up or slowing down), vector, average and instantaneous

Negative acceleration

slowing down in positive direction or speeding up in negative direction

Positive acceleration

slowing down in negative direction or speeding up in positive direction

Gravity

-9.80 m/s^2

Freefall

motion of an object when gravity is only significant force acting on it, g, vector, -9.80 m/s^2, mass does not affect freefall, if in a vacuum all objects will fall at same rate regardless of of size

Terminal velocity

velocity where it is not increasing anymore

Average acceleration

change in an object’s velocity during a measurable time interval

Instantaneous acceleration

change in an object’s velocity at a specific instant

Displacement

change in position having both magnitude and direction

Vector

quantity that has both magnitude and direction