Combo with "PHYS 1060: How Things Work" and 1 other

distance between me and Earth:

1 Earth radius

Every square inch of a room has ____ of air pushing down on it:

15 lbs.

how many miles is the Earth's atmosphere?

20 miles thick

What Newton's law is momentum based on?

2nd law (F=ma, or force=mass x acceleration)

2 identical arrows fired at target. One arrow is going twice as fast, the faster arrow will penetrate the target __________

4 times as much because the kinetic energy of an object is directly proportional to the square of its speed. That means that for a twofold increase in speed, the kinetic energy will increase by a factor of four.

a ball falling for .5 seconds would be falling at what velocity?

4.9 m/s^2 (half of 9.8 m/s^2)

Acceleration due to gravity and speed on International Space Station:

9.8 (same as Earth) because they're barely outside of Earth's gravity; they're also going 17,000 mph

acceleration due to gravity on Earth:

9.8 meters per second per second (9.8 m/s^2)

Angular displacement:

Angular displacement is the angle that a rotating body goes through. For example, if a skater skates in a circle around the center of the rink, stopping and starting at the same place, his or her angular displacement would be 360 degrees. The direction of the rotation is important.

Why does a rope swing get harder to hold on to when you start swinging?

Because of your own weight plus the centripetal force

Einstein's contributions to physics:

E=mc^2 (energy-mass); general relativity which shows the existence of space-time and the curvature of space-time as well as an expanding universe

Newton's third law:

For every action, there is an equal and opposite reaction

where did they discover gravitational waves?

LIGO

Who invented calculus?

Newton

If 2 things push on each other for the same amount of time with the same force is there a change in momentum?

No

If there's no force will momentum change?

No, momentum will be conserved

relative motion:

Relative motion is the calculation of the motion of an object with regard to some other moving object. Thus, the motion is not calculated with reference to the earth, but is the velocity of the object in reference to the other moving object as if it were in a static state.

what does E=mc^2 tell us?

a little bit of mass gets up a lot of energy;

mass:

a measure of an object's "stuff" (if something's mass is 2 kg on Earth then it's 2 kg in space)

energy:

ability to do work

Where in a loop does a car's weight act/not act centripetally?

acts centripetally at top of the loop and everywhere else it doesn't act centripetally (the track is doing the pushing and has to work the hardest at the bottom of the loop because it has to hold the weight of the car plus the centripetal force)

positive work:

adding energy to a system

doing work (work=?):

adding/subtracting energy to/from a system; force applied over a distance; refers to the process of transferring energy; work=force x distance

drag:

air resistance; depends on how fast you're going and surface area of object

Torque:

angular version of force; twisting force (torque=radius x force)

why are things attracted to each other?

anything massive makes a dent in space itself so when things are attracted to each other they are reacting to bent space

gravitational potential energy (=?):

as you lift an object up it's gravitational potential energy increases by an amount equal to the work you do on it; =mass x acceleration due to gravity x height (=mgh); means the higher something was, the harder it hit when it hit the ground

Large Hadron Collider

at CERN; largest and most powerful particle accelerator

normal force:

at a right angle or straight up and down; force is perpendicular to surface; force that is directed exactly away from surfaces

without air everything falls _____________

at the same rate

If a car is driving in a loop, where does it experience a centripetal force and where does it experience a centrifugal force?

bottom: centrifugal force; at top of the loop: centripetal force

How do planes fly?

by creating a little area of low pressure and a pressure differential that lifts the plane up (jet and propeller planes)

To go in a circle what force do you need?

centripetal force

How do jets fly?

compress air, light it, it explodes

most important characteristic of energy is that it's _______

conserved

Momentum always has to be _____:

conserved (reason guns have kickback is because a bullet leaves gun so quickly so same momentum has to go opposite direction)

Newton's fourth-ish law:

everything attracts everything else (universal law of gravitation)

Impulse:

force acting over an amount of time (force x change in time, which equals a change in momentum)

how to calculate amount of work:

force x distance

net force:

forces cancel out; net force means something can accelerate (no net force=no acceleration)

what is the thing that usually takes energy out of a system?

friction

friction:

get friction from a normal force; force between 2 surfaces (parallel to the surfaces); friction force always opposes motion; opposes the relative motion of 2 surfaces in contact with each other

How do you change something's momentum?

give it an impulse

you can take energy and put it into ________________

gravitational waves

Felix Baumgartner velocity pattern:

he was very high up where the air was very thin so there was less drag (air resistance) and so he fell very quickly at the beginning and slowed down as he got closer to Earth and the air thickened (he accelerated up--because he slowed down like by going 800 mph to 750)

One force acting on astronaut in space:

his own weight

speed:

how fast an object is moving; does not take into account direction (scalar quantity)

What type of collision has no kinetic energy lost?

if the collision is perfectly elastic

meaning of atom:

indivisible

Collisions are usually ______:

inelastic because energy is usually lost

what made the plate stay on the table when the tablecloth was ripped off?

inertia (the resistance of any physical object to any change in its state of motion)

units of energy:

joule, kilowatt-hour, calorie, BTU (water heaters)

How to jump over something on a skateboard:

jump up, not forward because if you jump forward the skateboard will go backwards from under you

What happens to kinetic energy in an inelastic collision?

kinetic energy is lost because the two things stuck together

what does kinetic energy depend on?

mass and velocity

momentum (p)=

mass x velocity (m x v)

at terminal velocity there is no ______ acting on you

net force

to accelerate you must experience a _______

net force

constant velocity:

no net force, but there is force (not accelerating=no net force)

Faster a gravitron is spinning the higher the _____:

normal force

What is the normal force and friction when riding the Gravitron:

normal force is centripetal (wall pushing people centripetally) and friction is up

horsepower:

not a unit of energy; measures how quickly you can use energy

Newton's first law:

objects at rest want to stay at rest; objects in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force (LAW OF INERTIA); an object that is not subject to any outside forces moves at a constant velocity, covering equal distances in equal times along a straight-line path

CERN

particle physics

orbiting:

planets actually going in straight lines, but follow the curves of space

Centrifugal force:

points away from the center of the circle

Centripetal force:

points toward the center of the circle

2 types of mechanical energy:

potential and kinetic

force:

pushing/pulling on something

acceleration (and unit):

rate at which an object changes its velocity; an object is accelerating if it is changing its velocity; unit: m/s/s (meters per second per second) (vector quantity); if direction changes (turning) you're accelerating

power:

rate at which you transfer energy (do work); rate of change of energy; change in energy/change in time

frictional forces almost always opposes _______

relative motion

inertia:

sluggishness; resistance of any physical object to any change in its state of motion (this includes changes to its speed, direction or state of rest). It is the tendency of objects to keep moving in a straight line at constant velocity.

If you're constantly going in a circle, what is also constant?

speed, velocity, and force (centripetal force)

spring force:

springs oppose what you do to them (pull slinky and it will bounce back to it's shape unless you pull too hard)

Newton's second law:

states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object; "the more stuff, the harder to shake" (AKA more massive something is the more force necessary to get it moving)

2 types of friction:

static and kinetic (sliding)

what type of friction is more impactful?

static friction because there is no relative motion

Angular momentum:

stays constant unless acted upon by a torque; is always conserved; defined as the product of the moment of inertia and the angular velocity

potential energy:

stored energy

negative work:

taking energy out of a system (friction)

Reason arrow hit falling target?

target and arrow fall at the same rate, even though one is experiencing a lot of horizontal motion and one is not)

what realms do Newton's laws apply to?

terrestrial and extraterrestrial

What do rockets push off of?

the exhaust (because there is no air or launchpad in space)

weight (w=?):

the force created by gravity (product of mass x gravity); w=mg; always pointing straight toward the center of the planet; can lose weight by reducing your mass or going somewhere where the gravity is weaker

velocity:

the rate at which an object changes its position; takes into account direction; 55 mi/hour east (vector quantity); unit: m/s

Angular velocity:

the rate of change of angular position of a rotating body.

What is acting centripetally with a rope swing?

the rope

all falling objects on Earth accelerate downward at ______ (not taking into account drag)

the same rate (9.8 m/s^2)

velocity of astronauts:

they have large tangential (sideways) velocity so they get into orbit

energy of when ball is thrown up in air

thrown up it's the fastest, stops at top (0 J) and then comes down slower because of air resistance and because when you toss it up it has a large upward velocity

Inelastic collision:

two things stick together after collision

Momentum is a _____:

vector (direction matters)

a constant acceleration causes a ball's ________ to change by the same amount every second

velocity

you are not accelerating if your _______ is constant

velocity

If a ball has twice the mass as another ball it also ______

weighs twice as much

What direction does a car's weight point when driving in a loop?

weight is always pointing down (weight is only centripetal at top of the loop)

What keeps people standing up in a Gravitron?

weight pulls them down but friction keeps them upright

Elastic collision (and what is conserved):

when two things collide and they swap velocities; momentum and energy is conserved