Physics

according to kepler, paths of planets are…

ellipses

newton discovered

that gravity is universal

according to newton, the greater the masses of interacting objects, the

greater the gravitational pull between them

according to newton, doubling the distance between two interacting objects

divides by 4 the gravitational force between them

what is the force of gravity on a 500 newton woman standing on earth’s surface

500 N

if the mass of earth somehow increased with no change in radius, your weight would

increase also

inside a freely falling elevator, there would be no

apparent weight for you

the earht’s gravitational field extends

both inside and outside the earth and throughout the entire universe

the direction of a gravitational field is

in the same direction as the gravitational attraction

a black hole is

simply the remains of a giant star that has undergone gravitational collapse

an asteroid exerts a 360N gravitational force on a nearby spacecraft. the force is directed

toward the asteroid

an asteriod exters a 360N grav force on a nearby spacecraft, if the spacecraft moves to a point 3 times as far from the center of the asteroid, the force will be

40N

if your mass, the mass of the earth, and the mass of everything in the solar sysyem were twice as much as it is now, yet everything stayed the same size, your weight on earth would

quadruple

if the radius of earth somhow decreased with no change in mass, your weight would

increase

if the earth’s mass decreased to 1/2 its original mass with no change in radius, then your weight wouldd

decrease to 1/2 your original weight

if the sun were twice as massive

its pull on earth would double and pull of earth on sun would double

an object is placed halfway between earth and moon, the object will fall toward

earth

the amount of grav force that acts on the space shuttle while in orbit is

almost as much as the shuttle’s weight on earth’s surface

a woman who normally weighs 400N stands on top of a very tall ladder so she is one earth radius above earth’s surface. how much would she weigh there

100 N

a very massive object A and less massive object B move toward each other under the influence od gravitation, which force is greater

same

2 objects move toward each other b/c of gravity. as the objects get closer and closer, the acceleration of each

increases

2 objects move toward each other b/c of gravity. as the objects get closer and closer, the force between them

increases

jupiter is 300 times as massive as earth yet its surface you would weight only about 3 times as much, this is b/c

jupiter’s radius is 10 times the earth’s radius

if you drop a stone into a hole drilled all the way to the other side of the earth, the stone will

speed up until it gets to thecenter of earth

half way to the center of the planet of uniform density, your weight compared to at the surface would be

1/2

inside a free falling elevator your

apparent weight is 0

passengers in a high flying jet feel their normal weight in flight while passengers in the orbiting space shuttle do not this is b/c the passengers in the shuttle are

above earth’s atmosphere

for astronauts inside the orbiting shuttle, there is no force of gravity acting on them this statement is

always false

the reason the moon does not crash into the earth is that the

moon has sufficient tangential speed

if the sun collapsed into a black hole, the earth’s grav attraction to it would be

the same

when a star collapses to form a black hoe, its mass

remains the same

how far must one travel to get away from earth’s grav field

can’t travel far enough

with respect to the stars, the moon

and the earth circle each other

which pulls on the oceans of the earth with the greater force

the sun

which is most responsible for ocean tides

the moon

the main reason ocean tides exist is rhat the pull of the moon

is greater on oceans closer to the moon and less on oceans farther from the moon

tidal forces in general are the result of

unequal forces acting on differet parts of a body

tides rise and fall

greatly different distances in different places

during an eclipse of the dun the high ocean tides on earth are

extra high

the best time for digging clams wjen the tide is extra low is during the time of the

new or full moon

there are no tides to be seen in pools b/c

all parts are practically same distance from moon

the tangential velocity of an earth satellite is its velocity

parallel to the surface of the eath

planets would crash into the sun if it weren’t for

their tangential velocities

what prevents satellites from falling

nothing, continually fall around earth

the circular orbit of a satellite orbiting the earth is characterized by a constant

speed, acceleration and radial distance

an earth satellite is in an elliptical orbit. the satellite travels fastest whe it is

nearest the earth

the fastest moving planet in the solar system is

the planet nearest the sun

it takes pluto a longer time to travel around the sun than the earth b/c pluto

has farther to go and goes slower

a woman on earth’s surface mass of 50 kg and weight of 490N if the woman were floating freely inside a space habitiat far from earth, she would have

less weight, same mass

a weightless astronaut is an orbiting shuttle is

like the shuttle, pulled by earth’s gravitation

compared to the period of satellites in orbit close to the earth, the period of satellites in orbit far from earth is

longer

force of grav does not work on a satellite when it is in

elliptical orbit

which force binds atoms together to form molecules

electrical

strip electrons from an atom and it becomes

poistive ion

to say that electric charge is conserved is to say that electric charge

can neither be created nor destroyed

the unit of electric change, the C, is the charge on

a specific large number of electrons

a main difference between gravivatioanl and electric forces is that the electrical forces

repel or attract

the electrical force b/w charges is strongest when the charges are

close together

the elecrical force b/w charges depends on the

magnitude od electric charges and the separation distance b/w charges

superconductors are noted for their

absense of electric resistence

rub electrons from your hair with a comb and the comb becomes

negatively charged

an electron and a proton

attract eachother

two protons attract each other gravitationally and repel each other electrically by far the greater is

the electrical repulsion

the primary purpose of a lightning rod is to

dischare the structure to whch it is attached

to say than an object is electrically polarized is to say

its charges have been rearranged

a balloon will stick to a wooden wall if the ballooon is charged

either neg or pos

when a car is struck by lightning the resulting electric field inside the car is

zero

charges on the plates of a charged capacitor reside on the surfaces

b/w plates

when the distance b/w two charges is halved, the electrical force between the chages

quadruples

partice A and B interact, A is twice the charge of B, compared to A the force on B is

the sa,e

if you comb you hair and the comb becomes positively charged, then your hair becomes

neg

neg rod is brought near a metal can on a wood table, you touch the opp side of the can, the can is then

positively charged

every proton in the universe is surrounded by

grav field and electric field

direction of electric field is the diretion of the force that it would exert on

a proton

charge carriers in a metal are electrons rather then protons b/c electrons are

loosely bound

longitutdial waves have

amplitude, frequency, wavelenght, speed

in a longi wave, the compressions and rarefractions travel in

same direction

not a trans wave

sound

vibrations of a trans wave move in a direction

at right angles

vibrations of a longi wave move in a direction

along the wave travel

rotation

object rotates about an axis (center of mass)

revolution

motion of an object turning around an axis that lies outside the object