physics midterm review

arrange these from greatest to least and from smallest to largest

m, km, mm, cm, mm

km, hm, m, cm, mm

know the metric base units and what each is used to measure, especially for mass, time a distance

mass- kg

time- s

distance- m

velocity- m/s

understand accuracy and precision and be able to relate the concepts to general questions as well as a collection of numeric values

accuracy- close to the true value

precision- close to one another or most amount of sig figs

what does " in a vacuum" mean and why is this important? How does this relate to acceleration and to velocity as an object falls

all objects fall at same rate at same acceleration. No air resistance

how is mass part of free-fall motion? if two object of different masses fall in a vacuum, which will hit the ground first

at same time

how is speed different from velocity

how fast something is traveling. speed is just an amount, velocity is speed with direction.

what happens to the velocity of an object that is falling freely without air resistance? What happens to it acceleration

velocity increases, acceleration is constant (due to gravity)

i toss a ball up and then catch it when it comes back down. what direction is the acceleration on the ball as it goes up? as it comes back down? what direction is the velocity on the ball as it goes up? as it comes back down?

a is always straight down towards center of the earth

what does the acceleration of all falling object depend on? is that acceleration the same on the moon

Gravity, NO!

be able to apply your understanding of acceleration due to gravity. is gravity different if the object is on the way up vs. on the way down? is the object still under the influence of gravity at the top of its path?

acceleration (due to gravity) is always the same as long as you are on earth

what is the difference between horizontal and vertical velocities and displacements? How are the horizontal movement and vertical movement related for an object in projectile motion

horizontal velocity stays the same throughout, vertical change bc gravity

what does "at the top of it trajectory" mean

top of motion

what is the horizontal acceleration for an object in free fall? the vertical acceleration? what about at the top of the paths trajectory

h- 0

v- -9.8

-9.8 is throughout the entire motion

an object is thrown from the ground upward at an angle. how does the object velocity change vertically and horizontally on the way up? at the top? on the way down?

it slows down on the way up then it is at rest then it speeds up on the way down

a single vector can be replaced by ____

2 component vectors

what is a scalar quantity and how is it different from a vector quantity? ex? Why is this important? what does quantity mean? what does "find the magnitude" mean

scalar- number only, how big/how much

what is the definition of projectile motion? Ex? What is the shape of the path followed by a projectile? Ex?

object that is launched into the air. the shape is a parabola. EX: plane flying, ball tossed in the air

i shoot a bullet and drop a bullet simultaneously from the same height. Which bullet hits the ground first? What is the only variable that this depends on?

same time; height

newtons first law

object in motion stays in motion or an object at rest stays at rest unless acted upon an outside force

inertia

an objects tendency to keep the same motion (or to resist change)

understand field forces and contact forces, including examples

field forces- don't require contact to exist (ex: gravity magnetic)

contact forces- to exist (ex: friction)

know newtons third law with examples

for every force but 2 objects there is an equal and opposite reaction force

understand the difference between weight and mass; how to measure and/or calculate each

fg= mg

g= 9.8 m/s

m-mass(kg)

does the law of inertia refer to moving object or objects at rest

Both

if i cause an object to move using a force, how much force is required to keep the object moving at the same speed

no force

another term for mass is

inertia

what is weight

force of gravity (Fg)

unit to show mass

kg

unit to show weight

N

3 things that can occur during an acceleration

speeding up, slowing down, changing direction

what cause accelerations

forces

if i drop a heavy (or light) object in a vacuum, what is the only force on that object? how can i calculate the amount of that force

Fg= mg

g= -9.8 m/s

if I'm given a mass and a force, how can i calculate acceleration

a= Fnet/m

what does net force mean

sum of all forces acting on an object

what is the net force on an object that is dragged without acceleration? what does with our acceleration mean?

if a= 0 then Fnet=0

constant speed or at rest

when should you use 9.8 m/s as the acceleration on an object whose force you're trying to determine? when should you not use 9.8 m/s

when an object is moving up or down

moving horizontally- don't use 9.8 m/s

if a very small object and a very large object run into each other, which object applies the grater force to the other?

same

is there ever a time when newtons 3rd law does not apply

-when you are talking about one object it won't apply

- only works between two objects

what is angular (rotational) speed

how many degrees per second, the same throughout an object

what is tangential (linear) speed

how many meters per second traveled, greater as you move away from axis

on a rotating merry go round, the child in the middle has ___ angular speed as compared to the child hanging on to the bars on the edge of the merry go round, and he (the child in the middle) has ____ tangential speed as compared to the child on the edge

same;less

to make a turn, your car must have a sufficient friction force. what type of force is the friction acting as? what direction does this force point when drawn as a vector?

centripetal force (Fc) towards the center of the circle

we have talked a lot about how there is no such thing as a centrifugal force, but there definitely is the feeling of being pulled outward when you rotate. Why does it feel like you're being pulled out when you're actually only being pulled inward?

inertia

newtons law of universal gravitation says that everything pulls on everything else. why don't you notice the pull of your pencil acting on you as you work on this review? what are the factors that affect the force of gravity

not enough mass; mass and distance

an object that moves in a circular path has a constant acceleration caused by the centripetal force. Which direction is the acceleration pointed when drawn as a vector?

towards the center of the circle

greek symbol for "change in "

delta