physics I final
an ideal gas in a very rigid sealed container is in a state (Pi, Vi, Ti, ni). heat is added to that the pressure doubles. the final state (Pf Vf, Tf, nf)
(2Pi, Vi, 2Ti, ni)
a roller coaster car , mass=m, Is on a track that forms a circular loop (radius =r) in the vertical plane. if the car is to just maintain contact with the track at the top of the loop, what is the minimum value for its speed at that points?
(rg)/2
a neutron star collapses so that its final radius is 1/10 as much as its initial radius, but its mass remains the same. if it had an initial period of rotation of 10 days its final period
0.1 days
the position of a particle moving with simple harmonic motion is x= (4cm)cos8it. he period of the motion is
0.25 sec
consider the 3 objects each of the same mass M and radius R : 1- solid sphere I= 2MR^2/ 5 2- solid disk= I=MR^2/2 3- HOOP= I=MR^2 all released at the top of an inclined plane and proceed down without slipping. whats the order do they reach the bottom of the incline ?
1,2,3
a neutron star collapses so that its final radius is 1/100 as much as its initial radius, but its mass remains the same. the moment of inertia od the star is I=MR^2/5. IF IT HAD AN INITIAL PERIOD OF ROTATION OF 10 DAYS ITS FINAL PERIOD will be
1-*10^-4 days
kinematics one dimensional equations
1. X= Xi + Vi t + 1/2 at^2 2. Vf= Vi+ at 3.(Vf)^2- (Vi)^2=2a(delta X)
AS OF JUNE 2009 THE TOP 10 ranked supercomputer n the world was roadrunner at Los almost, capable of sustained performance of over 1.1 peta (10^15) calculations per second. how many calculations does this machine perform in millisecond?
1.1*10^12
the distance to a point source is decreased by a factor of 4, by what additive factor does the intensity level change?
1.2 dB
kepler's lAW
1.PLANETS move in elliptical orbits with the sun at one focus 2. as a planet moves in its orbit it sweeps out equal areas in equal times
1/2 the pressure
1/2 the volume
an object is thrown with a speed of 14m/s. how high above the projectile point does it reach
10m (think that gravity pulls and decrease its speed ) going downward gravity add
2 cars traveling opposite direction are 500m apart. the speed of B is 20 m/s and the speed of A is 30m/s. in how much time will they meet?
10s
if a vector has component Ax<0 an Ay<o then the angle that this vector makes with positive x-axis must be in rage
180 to 270
force has a dimensions of mass times acceleration. the SI unit of force is the Newton (N), N= (Kg*m)/s^2 and CGS unit of force is the dyne(d), d=g*cm/s^2, where g sands for gram. 1 kg= 10^3g, 1m=10^2 cm. the equivalence of Newton and dynes is
1N= 10^5 d
inelastic Collision
2 OBJECTS COME TOGETHER AND STICK where the total kinetic is NOT conserved Momentum Is Conserved
elastic COLLISION
2 objects collide and bounce off each other where total kinetic is CONSERVED MOMENTUM IS CONSERVED initial momemntum = final momentum
the frequency range of human hearing is about
20 Hz to 20,000 HZ
a uniform cube od side L is placed on the floor. another cube of the same material and of side L/2 is placed on top of the large one. how far from the floor is the center of mass of the system?
21 L/26
the moment of inertia of a solid cylinder about its axis is given by MR^2/2. if this cylinder rolls without slipping the ratio of its rational kinetic energy to its transactional kinetic energy is:
2:1
internal and external forces follows ------ Newtons Law
3rd law: where the net force acting on a system of objects is the sum of the forces applied outside the system and the forces acting inside the system action-reaction which will equal to ZERO
A vertical spring has a mass hanging from it, which is displaced from the equilibrium position and begins to oscillate. At what point does the system have the least potential energy?
AT THE EQUILIBRIUM POINT
at what orbital radius (around the sun) would the earth be if its mass where 10 times larger and the year 96 months long ? ( the actual orbital radius is denoted Re)
4.0 Re
by what amount does the intensity level increase when you tripled the intensity of a source of sound
4.8 dB
a person walks 8m in a straight line east of north and ends up 4m eat and a certain distance north. what direction in degrees east of north did the person walk
45 degrees
a mass on a spring in simple harmonic motion has amplitude of A and a period of T. what is the total distance traveled by the mass in a time interval T?
4A
is centripetal force caused by conservative or non-conservative forces?
BY CONSERVATIVE, or non-conservative OR both
lightning is a killer in forida .......... people have been kills by lightning strikes ..... over 10 miles away and clear bleu ..........there is an easy way to estimate the distance strike.... estimate the time delay in seconds b/w being the flash and hearing the sound of the thunder . the speed of sound at sea level is apron. 1100 ft/sec. approx. how manu seconds/ mile is the delay b/w the flash and the hearing the thunder? ( 1 mile =5280ft)
5seconds/ mile
person walks 8.0 m in a straight line west of north and ends up 4.0 m west and a certain distance north. How many degrees north of west has the person walked?
60
a rescue airplane is flying horizontally with speed of 100m/s at an altitude of 180 m above the ground. it tries to drop a care package on some refugees the package should be released
6s before the plane passes over the heads of the refuges
A conservative force is
A and B : A] one such that the work done between any two points is path independent. [B] one that does zero work on any closed path.
2 children are riding the merry-go-round that is turning. child a IS SITTING AT A GREATER distance from the axis of rotation that child B. which child has the large linear displacement
CHILD A
when the mass of simple pendulum is tripled the time required for one couple vibration
DOES not change
Energy conservation
E= K+U = 1/2mv^2 -G(mM/r)
block of mass "m" is at rest on an inclined plane that makes an angle theta with the horizontal. the force of static friction "f" must be such that
F= mg*sin(theta)
springs and Hooks law equation
F=-Kdelta x delta X: is the distance the spring is displaced from equilibrium K: IS THE FORCE CONSTANT OF THE SPRING
Force
F=ma ==> SI: in N defined as a mass multiplied by an acceleration
generally speaking the friction between 2 dry solids is proportional to their area of contact
False
Kinetic fRICTION
Fk=uN , Not a vector Us= static friction Uk= kinetic friction
a boy and a girl are riding on a merry go-round that is turning. the boy is sitting twice as far as the girl from the merry go round center. if the big and the girl are of equal mass, which statement is trues about the BOY'S moment of inertia with respect to the axis of rotation?
HIS moment of inertia id 4 TIMES the GIRL'S
2 objects are dropped from a bridge an interval of 1.0s apart. during the time that both objects continue to fall, the separation
INCREASES
As the temperature of the air increases, what happens to the velocity of sound? (Assume that all other factors remain constant.)
IT increases
F(cp)
Is a force that must be present tp cause circular motion can be tension on string +BALL friction between tires +road force of gravity causing a satellite or moon to orbit earth
work energy
K= 1/2 mV^2 in joules
which quantity is always conserved during collision ?
LINEAR momentum
which one of the following is NOT a vector: acceleration, displacement, force, mass, or velocity
Mass is not a vector
a uniform beam of mass M is supported by a column at each end. a mass M'2 is placed o1/4 of the way from the left end. what is the force provided by the support at the left end?
Mg
which of the following is unit of torque ?
N*m or Joule * second
a box placed on table is at rest. it feels 2 forces: the gravity force and the supporting force from the table . are these forces an action-reaction pair forces?
NO, because they act ON THE SAME OBJECT
can work be dome on a system if there is no motion ?
NO, since work involves a non-zero displacement
a child runs toward a rotating merry-go-around and jumps onto is. the final angular velocity od the system of the child and the merry go around is independent of
NONE OF ABOVE
Units of springs
Newton
Units of the pulleys
Newton
unit of momentum
Newton *second
what do we measure force by
Newton: N=KG*m/s^2 1 N is the amount of force we ould have to apply to a mass of 1kg to make it accelerate at the rate of 1m/s^2
Unit of K
Newtons / meter N/m
stefan-Boltzmann law
P net= e*theta8A (T4-T4 surrounding)
an ideal monatomic gas undergoes a reversible isothermal expansion where V2 =5V1. how much work is dome by the gas in this process, in term of the initial pressure and volume?
P1V1 LN(5)
rotational work and power
P= t*omega
MKS unit of energy is joule .... if power is defined as energy / time with of the following ..
P=F*v
potential energy for springs
PE= 1/2 Kx^2 PE DEPENDS ON X^2 because its positive so PE IS ALWAYS POSITIVE units in joule
Gravitational potential energy
PE= mgy y: change in vertical position
when object falls gravity does
POSITIVE WORK SO THE OBJECTS POTENTIAL ENERGY DECREASE and kinetic increase
ideal gas equation
PV= nRT n: #of molevules R: gas constant 8.13 J/(mol*k) T: temp P: pressure V: volume
An external pressure applied to an enclosed fluid is transmitted unchanged to every point within the fluid" is known as
Pascal's principle
iceberg are known to float 92% of their volume below surface of the water some scientist predict that climate change due to a large spike of CO2 in our atmosphere will melt most pf the iceberg polar cap ... melting the ice in the polar caps that is currently floating in the oceans cause the earths oceans level to
Rise
car a IS TRAveling at twice the speed of a car B. they both hit the brakes at the same time and undergo indentical declarations? how does the distance required for car A to stop compare with that for car B?
A travels four times the distance equation: 4*distance of B
pulleys
T= mg in N designed to change the direction of the rope and so the tension they act like force multipliers , they are masles
period
T= the time it takes to complete 1 revelation : (2pi/ omega )*s
a man walking toward the right in a normal manner is acted upon by a force of static friction toward the left
TRUE
galileo demonstrate that in the absence of air resistance al bodies fall with same acceleration
TRUE
the celsius and the farnheit temperature will have the same numerical value when
Tc= -40 C
gravitational PE
U= -G (mM of earth /r) negative because gravity attracts, a positive potential would be repulsive and push aways PE is not a vector
if it is hard to start a stationary object moving than to keep it moving because e
Us > Uk static friction greater than kinetic friction
A BLOCK OF MASS "m" slides without friction on a table with speed "v". it hits and compresses a spring of force constant "k" by a distance "l'. the spring then expands again ejecting the block opposite direction as it was originally traveling. what is the speed pf he object after it is ejected by the spring
V
escape velocity
V ESCAPE = radical (2GM of earth /R of earth )
trolleys law
V=radical(2gh)
WORK equation
W = F*d in: joules units: N*m = Joules
work theorem : WET
W total= Kf- Ki= 1/2 (Vf ^2- Vi^2) VALID for any force
a block moves a distance d along the horizontal surface. the work W done by the force F is:
W= F cos (theta) d
Gravitational work
W= mgh
spring force : work to stretch or compress a spring from equilibrium
W=1/2 Kx^2
about which axis, x or y , is it easier to rotate the system of 5 identical balls
Y-axis
work done by static friction is always
ZERO
THE FORCE LAW FOR a spring is F= -Kx is displacement from equilibrium. from dimensional analysis what are the fundamental units [L][M],[T]. of K
[M]/[T^2]
2 stars with masses M and 2Mare separated by distance l b/w their centers. if an asteroid becomes trapped at rest b/w the stars how far from the less massive will it be?
[radical (2)-1]*L
a roller coaster is on track forms a circular loop in the vertical plane. if thecae is to just maintain contact with track at the top of the loop, what is the minimum value for its centripetal acceleration at this point?
a "g" downward
a packing crate slides down an inclined ramp at constant velocity. thus we can deduce that
a FRICTIONAL force is acting on it
to make an object Move in a circle with constant speed what must we do
a force must act on it that is directed TOWARD the center of the circle
during the time that the acceleration of a particle is constat its velocit vs time curve is
a parabola opening DOWNWARD
center of mass
a system behaves as if all of its mass was concentrated at the center mamss and as a result a system can be BALANCED
streamline
a tangent to the velocity vector of a fluid element that shows direction the fluid element will travel at any instant in time "ideal fluid"
equation for centripetal force
a(cp)= V^2 / r for acceleration units : m/ s^2 F(cp)= m *( V^2/R) FOR FORCE Units: N
the position of a mass on a spring is given by x(t) Acos (wt). the kinetic energy and potential energy equal to each other at what position?
a/radical 2
a box of mass m is sliding along a horizontal surface with coefficient of kinetic friction uK. only the surface is touching the box. let the positive x axis lie in the direction the box is sliding. the acceleration of the box is
a=-g*u*k*i
a simple pendulum consists of a mass m attached to the end of a thin rod of length L. the period T of the pendulum might depend on the mass m the length L and the acceleration of gravity g ......what are acceptable values of the dimensionless exponents a,b, and c?
a=0 , b= 1/2, c=-1/2
a block of mass M is sliding down the include plane which has a coefficient of kinetic friction with the block uk. to find the magnitude use this equation
a=g(sin theta-uk cos theta)
A STUDENT SUSPENDs a pendulum vertically from inside the roof of a car. as the car pulls away from a stop, the student observes that the string now makes an angle theta with the vertical. what is the acceleration of the car
a=g*Tan(tehta)
an astraunaut is in a capsul in a stable orbit, about 2 earth radii fro the centre of earth she weight
about 1/4 of her weight on the surface of earth
consider 3 drinking glasses. all 3 have the same base, and all tree are filled to the same depth with water. Glass A is cylindrical. Glass B is wider ate the top than at the bottom, and so holds less water that A. which glass has the greatest liquid pressure at the bottom?
all three have equal non-zero pressure at the bottom
zeroth law of thermodynamics
allow to measure temp. differences b/w objects of the same temp
friction force
always acts OPPOSITE to the direction of motion ex: sliding a book across a table F=uN u: friction coef. unitless
from down here is notes
and from here up is test notes
a puck on a horizantal frictionless surface is attached to a string that passes through a hole in the surface as shown in figure.(table with hand underneath rotating the ball). , as the puck rotates about the hole the string is pulled donward, bringing th epic closer to the hole during this process
angular momentum is UNCHANGED, angular speed and tangential speed are INCREASED
circle the answer that best represent the vector Q-P in the figure
answer is A
the person who first discovered the principles of buoyancy and displacement was, and was wearing what at the time
archimedes of syracuse wearing nothing at all
Ch2,3,3: kinematics is
are particles in motion
state the second keeper's law of orbital motion
as a plane moves in its orbit, it sweeps out an equal amount of area in an equal amount of time
K av= 3/2 kT
average of kinetic energy
Thermal expansion
bi-metalic strip changes in temp cases the length of an object to change. heating causes an object to grow longer an coolung causes its length to shorten
2 identical balls are thrown from the top of a building with the same speed. ball 1 is thrown horizontally while ball 2 thrown at an angle theta below the horizontal. neglecting air resistance when the balls reach the ground below
both balls will arrive with the same speed
the blocks of mass "m1" and "m2" are released from the top of 2 frictionless inclines planes of the same height making 30 and 60 angles with the horizontal direction respectively. which of the blocks is going faster when it reaches the bottom of its respective incline?
both blocks have the same speed at the bottom
a thermal isolated system is made up of a hot piece of aluminum and a cold piece of copper; the aluminum and the copper are in the thermal contact. the specific heat capacity of aluminum is more than double that of copper. which object experiences the greater magnitude gain or loss of heat during the time the system takes to reach thermal equilibrium?
both the aluminum and the copper experience the same magnitude of gain or loss of heat
You are driving a late model convertible at the 65 mph limit with its soft ragtop roof up and the windows closed. You observe that the roof
bows outward
a figure skater is spinning slowly with arms outstretched. she brings her arms in close to her and her moment of inertia decreases by 1/2 . by what factor does her rational kinetic energy change ?
by 2 ,
when object partially submerged how we measure its weight
calculates its whole weight
Centripital force
center seeking when the speed or the direction of the velocity changes in a circular motion , The direction of the velocity also changes in circular motion
what is it when the velocity of an object changes but its speed remains the same:
circular motion with constant speed FYi(v: direction is changed )
the process whereby heat flows of molecular collisions is referred to as
conduction
a ballerina begins with he arms outstretched and spins faster as she brings her arms closer to her body. this is explained in terms of
conservation of angular momentum
the ice skater brings her outstreched arms closer to her body and spins faster this is an example of
conservation of angular momentum
bernoullis principle
conservation of energy for a fluid undergoing steady flow along a streamline the sum of all forms of mechanical energy is the same at all points on the streamline
the recoil of a rifle is explained in terms
conservation of linear momentum
the recoil of the riffle is explained by
conservation of linear momentum
angular velocity
correspond to V
angular acceleration
correspond to a
if the celsius temperature of an ideal gas changes fro 327C to 27 C the Vrms speed of the molecules
decreases by a factor of radical 2
1st law of thermodynamics
delta U = Q - W
radianns are
dimensionless s=rTheta
if you start from th bakery travel to the cafe and then to the art gallery in 2hours. what is the distance you traveled? what is the displacement ?
distance:10.4 Km add all displacement: 2,4 km to the south
double the pressure
double the volume
imagine that the metal head of a hammer lose in order to get the hammerhead tight again you should
drop the hammer with handle end down
heat
energy transferred between objects because they are at different temperatures matter DOES NOT contain heat
conservation of energy 1st law of thermodynamics
ennergy cannot be created or destroyed, it only change form
a ball is thrown up into the air, ..... when it is rising and aerates half of its max height the net force acting on it
equal to its weight
A rigid bod is made of 4 masses sticks that form a square of side L. identical masses m are placed at the 4 corners of the squares. the square rotates about an axis that runs along a side of the square. find the moment of inertia of the body
equation: 2mL^2
a ball is ties to a string and twirled in horizontal circle above the persons head. if the string were to break the ball would
fly off in a straight line agent to the circle and then move in parabolic trajectory
impulse
follows newton 2nd law as far as the masss is constant is chnage of momemntum: which is the average force F times the lenght of time "t" that 2 surfaces are in contact, I= F average * delta t = delta p (momentum ) units in: N*s = kg*m/s
apparent weight
force felt from contact with floor or scale like elevator ex.
conservative forces
force that does zero work any path where you start an end at the same place like gravity
Kg. m/ s^2 is a unit of
force which is "newton"
what is the difefrence between the pressure inside and outside a tire
gauge pressure
Negative k : F=-Kx
gives magnitude AND direction
Poistive K : F= +Kx
gives magnitude ONLY
light carries momentum, so when a beam impinges on a surface it will exert a force on that surface. if the light is reflected rather than observed the force will be
greater
Ideal Fluid
has no viscosity states that with any change in the speed of the fluid there is a change in pressure
latent heat
heat added or removed to effect a phase change equ. Q= mL units in Joule USED TO CALCULATE HEAT NECESSARY TO MELT SOMETHING m: mass L : four from Q= mCAT
Work positive
if the FORCE has a component in the direction of motion Theta b/w -90 and 90 degrees==> -90 <theta<+90
work is negative
if the force has a component OPPOSITE to the direction of motion theta is b/w + 90 and + 270degrees 90<theta< 270
work is zero
if the force hasNO component in the direction of motion theta= +/- 90 degrees
a truck is as twice as heavy as a car. they both are driving along horizontal elevated read that suddenly ends. the two vehicles fly off so their initial velocities are horizontal they hit ground. the car hits the ground in about 2 sec. the truck hits the ground in
in about 2 second
work = F cos (theta)*d
in joules
double speed
increase Kinetic Energy by factor go 4
the length of a pendulum is increased by a factor of 4. the period of the pendulum ..
increase by a factor of 2
a car traveling with a velocity of magnitude "v" is decelerated by a constant acceleration of magnitude "a". it travels a distance "d" before coming to rest. if its initial velocity were doubled, th displacement required to stop would
increase by a factor of 4
an open pot of water is boiling ion a gas stove when someone raises the flame. the result will be
increase in the rate of boiling
doubling only the amplitude of a vibrating mass and spring system produces what effect on the system's mechanical energy?
increases the energy by a factor of 4
U= 3/2 NkT
internal energy of an ideal gas , reason for molecules to not stick together
a railroad car of mass m and speed v collides and sticks to an identical railroad car that is initialy at rest. after the collision, the kinetic energy of the system
is HALF as much as BEFORE
when gravitational equipotentials are closer together, the corresponding terrain
is STEEP
potential energy
is a storage system for kinetic energy PE converted to KE PE = 1/2 Kx^2 Wc= -( PE final - PE initial), units Joule we can choose the zero
accceleration
is a vector , it has both magnitude and direction
displacement
is a vector measured in meter how far did you go from a starting point, can be negative
pressure
is force divided by area unit pascal Pa. = 1N/m^2 P=F/A
if you double the absolute temperature of an ideal gas, the average kinetic of the molecules
is multiplied by 2
the normal force
is perpendicular to the surface of contact
mass density
is t is intristic: do not depend on how much stuff there is
Tension
is the force applied on a string from distance source
constant linear momentum
is the momentum of an object of mass "m" that os moving in a straight line with velocity "v"
Work
is the product of 2 magnitude. it is a scalar. WHEN OBJECTS MOVE. If object NOT moving there is NO work
fluid flow and continuity
is the volume of flu displaces per time at point 1 and 2 p1a1v1= p2a2v2
isochoric
iso : same Choric: volume constant volume delat U= Q
isobaric
iso: same baric: barometer measure of the same pressure
isothermal
iso: same , Thermal: Temp constant temp if T=0 Q=W temp CANT change pressure and volume can change
a freight car moves along a frictionless level railroad track at constant speed. the freight car is open top a large load of coal is suddenly dumped into the car. what happens to the speed of the freight car?
it DECREASES
a sample of an ideal gas slowly compresses to 1/2 its original volume with no change in temperature. what happens to the rms speed of the molecules in the sample?
it does not change
conservation of linear momentum
it is conserved, it is the net force acting on an objects is zero
a rock is thrown rom ground level at some angle above the horizontal with a certain velocity. it reaches its highest point and starts falling down. what is the magnitude of the velocity of the rock right before it hits the ground
it is equal to the magnitude of its initial velocity
mass only
it is extrinsic: which does depend on stuff there is
3rd law of thermodynamics
it is impossible to lower the temperatur of an obebjct to absolute zero in a finite number od steps
mass density
it measures the concentration of mass or how much physical stuff is packed into a volume p=m/v
a 16 Kg fish is weighed with 2 spring scales, each of negligible weight. what will be the readings on the scales?
it will be the SUM of the 2 readings = 32 kg
what is weight
its a force FW=mg in N where g: is the earths gravitational acceleration
a baseball is thrown straight up and falls back in the hand of catcher. we can say that during its flight
its acceleration is constant throughout
an object is thrown vertically up near earths surface with initial velocity v0 at the maximum height of its trajectory:
its magnitude of acceleration is "g" direction is pointed straight down and it has velocity UPWARDS
a stone is thrown straight up. when it reaches its highest point
its velocity is ZERO and its acceleration is NOT ZERO
for general projectile motion which staten is true when the projectile is at the highest point of its trajectory
its velocity is perpendicular to the acceleration
in the finger masses m1 an m2 are such that m1>m2 and they lay on level frictionless surface. we can apply a horizontal force F either from the left or from the right the contact force between masses m1 and m2 is
larger when it is applied from the right
light carriers momentum so when a beam impinges on a surface it will exert a force on that surface. if light is reflected rather that absorbed. the force will be
less
equipotentials
lines corresponding to constant values in PE
in may cartoon shows a character runs of a class realizes ....... if the physical situation is portrayed correctly from the vantage point of an observer at the top of the class leaning over the edge the pitch of the dream should be
lower that the original pitch and decreasing as he falls
suppose tha an object travels from point in space to another. make comparison b/s the magnitude of the displacment and the distance traveled.
magnitude of the displacement is either lLESS THAN or EQUAL to the distance traveled.
ideal springs are
massless, they obey Hooks law used to measure other unchain forces
lower case "c"
means specific heat only depend on the substance
what if a=0 for either direction
means that all the forces acting on an object cancel each other out
ALL REAL PROCESSES ARE REVERSIBLE
means that everything you o will contribute to the heat of the universe
sinking
means the weight larger than the buoyant force
mechanical heat
means transfer of heat
power
measure of how quickly work is done , its a scalar P= energy/time , ==> units j/s = Watts :W
rational kinetic energy
measured in joules
moment of inertia
measures the object's resistance to changes in angular velocity
liquid
molecules are close together
ideal gas
molecules are sufficiently far apart that we can assume no interaction among them a gas will expand to fill all available space
what is the quantity used to measur an objects resistance to change in rational motion?
moment of inertia
projectile motion
motion IN EACH DIRECTION IS INDEPENDENT USED THE KINEMATICS EQUATION
oscillatory motion
motion of a spring that goes back and forth
when the force the springs exerts is in the direction opposite to the objects motion (comopress) the work done is
negative: object moves slower
2 men joel and jerry push against a wall. jerry stops after 10 min, while joel is able to push for 5 mins longer. compare the work they do
neither of then do any work
linear momentum is conserved when
no outside forces act on the system
a 75. kg astronaut wearing 25 kg space suit while floating in space fires a little gas jet shoots out a blast of 10.0 of gas in opposite direction he in turn
none of these
Normal force
normal means perpendicular this is the force that a surface will exert on a body perpendicular to it
distance
not a vector measured in meter, always positive
a heavy boy and lightweight girl are balanced an a massless seesaw. if they both move forward so that they are 1/2 their original distance from the pivot point what will happen to the seesaw?
nothing the seesaw will still be balanced
Newtons 1ST LAW : inertia
objects at rest remain at rest and objects in motion continue to move at the same velocity unless acted on by an outside force
weight going down
objects moves faster
an object oscillating with simple harmonic motion complete a cycle in a time T. if the object's amplitude double
only the objects period double
an arrow is shot into the air on a parabolic path to a target. at its highest point
only the vertical component of the velocity vector is zero
when i the average acceleration of an object equal to the instantaneous acceleration?
only when the acceleration is constant
when can the average velocity of an object be equal to the instantaneous velocity?
only when the velocity is constant
when is the average velocity of an object equal to the instantaneous velocity ?
only when the velocity is constant
ithe speed of a wave traveling on a string which is fixed at both ends v= Fu here f is the tension ...... the power O and q required for dimensional insistent ........
p= +1/2, q=-1/2
gauge pressure
pressure in your tire P gauge= P- P atmospheric
weight of atmosphere
pushes down wich equalize the pressure in you body or object exerted on: reason for not being crushed 1 bar= 10^5 pa P atmospheric= pgh p= pressure. g= gravity, h= height
A CAR TRAVELING WITH VELOCITY "V" is decelerated by a constant acceleration of magnitude "a" IT TRAVELS A distance "l" before coming to rest/ if its initial velocity were doubled, the distance required to stop would
quadruple
the period of a pendulum is that it takes the pendulum to swing back and forth once. if thinly dimensional quantities that the period depends on are the acceleration of gravity, g, and the length of the pendulum,L, what combination of g and L must the period be proportional to?
radical (l/g)
which is not unit of acceleration
radical (meter*foot/second2)
torques cause
rotational translation
someone weights 150 lbs on earth. on planet of four times the earths mass and twice the earths raduis what would he weight
same 150lbs
work done on object is positive/ negative
speed increase/ decrease
a disk, a hoop, and a solid sphere are released at the same time at the top of an inclined .......they have the same mass and radius, they roll without slipping. in what order o they reach the bottom?
sphere, disk, hoop
Springs and Hooks Law
springs exert force that is proportional to the amount of X where it is stretched or compressed Hooks law very important it is applied to measure the force that holds atom together
Newtons Second law
states : the acceleration is proportional to the force, the greater the force the greater the acceleration Sum(Fx) =ma of x-axis Sum (Fy)= ma of y-axis
As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires and the road is
static friction
rolling without slipping depends on
static friction between the rolling and the ground
static equilibrium
sum F right =sum F left sum F up= sum F right sum t cw= sum t ccw
A PROJECTILE IS LAUNCHED ON A LEVEL GROnd with speed v0 at an initial angle alpha above the horizantal. if g is the acceleration of gravity, the time of flight of the bullet to return to the ground is given by formula
t= (2v0/g )*sin (alpha)
###Newtons 2nd law for rotation torque equation
t= I alpha
torque equation
t=r* sin(theta) F +: COUNTERCLOCKWISE -: CLOCKWISE also known as cross product between raduis and the force vector units
with the same question above the block mass M is STATIC on the inclined plane, whith a coefficient of static friction with the block us. what must be true for the block to remain static?
tan theta< Us(static coefficient )
a disk and hoop of the same mass and radius are released at the same time at the top an inclined lane. which object reaches the bottom of the incline first?
the DISK
Astronaut in space took a light spring of known spring constant attached a mass to it and set it oscilating. by measuring the period they can determine
the MASS of the bob
2 EUQAL forces are applied to a door. the 1st force is applied at the midpoint of the door, the 2nd force is applied at the doorknob. both forces apple perpendicular to the door. which force exerts the greater torque
the SECOND : the boor knob
the speed of a wave on a rope is independent of
the amplitude of the wave
ANGULAR momentum cannot be conserved if
the angular acceleration changes
in rotating system when no outside TORQUE acts on a system
the angular momentum is CONSERVED
the air in a room is composed principally od nitrogen oxygen and carbon dioxide ..... if the 3 gases coexist in thermal equilibrium
the average kinetic energies of their molecules are equal
thermal equilibrium
the average kinetic energy of the molecules is THE SAME for both objects an so there is no heat between them
which statement is correct about the relation b/w THE AVERAGE SPEED and magnitude of the average velocIty FOR ANY MOTION?
the average speed GREATER than or EQUAL to the magnitude OF THE AVERAGE VELOCITY
which statement is correct about the relation b/w THE AVERAGE SPEED and MAGNITUDE of the average velocity for any motion?
the average speed is always greater that or equal to the magnitude of the average velocity
a man holding a rifle horizontally fires a bullet. at the same instant an empty cartridge is ejected to the side fro the same height with zero vertical velocity. let air resistance be negligible.
the bullet and the cartridge git the ground at pretty nearly the same time
the cart on an air track is accelerating in the x direction with the air on frictionless. when the air is abruptly turned off restored friction the cars velocity is seen to decrease. we can say that
the carts acceleration is now in the x-direction
A disk (I = 1⁄2 MR2) and a hoop (I = MR2) of the same mass and radius are released at the same time at the top of an inclined plane and allowed to roll without slipping to the bottom.
the disk always win
Jacques and François meet in the middle of Lake Champlain (on the Quebec side) while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes François' canoe with a force F! to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system?
the final momentum is zero Kg*m/s BUT the final kinetic energy is positive
if distance reduce by 1/4
the final speed reduce by 1/2
when parachutist jumps from an airplane he eventually reaches a constant speed called THERMAL velocity this means
the force of air resistance is equal to the weight of the parachutist
a simple pendulum consists of a mass M attached to a weightless string of length L. for this system when undergoing small oscillations
the frequency is independent of the mass M
what if the mass increase
the greater the mass the less acceleration
the greater the force and distance
the greater the work
which statement is true about the relation b/w the INSTANTANEOUS SPEED and the MAGNITUDEof the instantaneous velocity ?
the instantaneous speed is always EQUAL to the magnitude of the instantaneous velocity
a rifle fires a bullet and recoils the mass of the rifle is much greater than the mass of the bullet
the kinetic energy of the rifle is less than that of the bullet
bernoullis principle follows that the faster the fluid moving
the lower the pressure
the higher the speed
the lower the pressure
an object slides on a surface with friction. the coefficient of kinetic friction depends on
the material of the object
center of mass
the mobile is balanced when the center of mass is directly under the suspension point. this mean that its weight creates zero torque
A merry-go-round spins freely when Janice moves quickly to the center along a radius of the merry-go-round. It is true to say that
the moment of inertia of the system decreases and the angular speed increases
an object of mass "m" sits on a flat table. the earth pulls on this object with force "mg" which will call the action force. what is the reaction force?
the object pulling upward on the earth with force "mg"
A croquet mallet balances when suspended from its center of mass, as shown in the figure(above). If you cut the mallet in two at its center of mass, as shown, how do the masses of the two pieces compare?
the piece with the head of the smallest has the greater ma
turning point
the point on the graph where the ball stops momentarily and turns around, where PE is greates
CM: center of mass
the point where the system can be balanced in a uniform gravitational field
when heights are unequal in the U tube
the pressure is different
LINEAR MOMENTUM
the product of the mass and the velocity of an object p=mv, units Kg*m/s P: is a vector with both magnitude and direction
consider a plot of the displacement (vertical axis ) vs applied force (horizontal axis ) for an ideal elastic spring. the magnitude of the slope of the curve would be
the reciprocal of the spring constant
on going from the ground level to the second floor you can either use stairs or elevator. in which situation does GRAVITY do more work on you?
the same
a truck is towing a car whose mass is 1/4 that of the truck. the magnitude of the force exerted by the truck on the car is 6000N. the magnitude of the force exerted by the car on the truck is
the same 6000N
the absolute pressure measurement to a point within a liquid stored in a large open tank is independent of
the shape of the tank
fluid is flowing steadily along a wide pipe that becomes narrower. as the fluid passes from the wide part to the narrow part
the speed increases and the pressure decreases
neglecting air resistance when you toss a stone straight up in the air fro earth's surface which of the following statements is true for the upward motion of the stone.
the stones kinetic energy DECREASES while its gravitational penitential energy increases
Mechanical energy
the sum of potential an kinetic energies of an object, from PE to KE and vice versa never lost E total= PE+KE WHICH IS : Etotal = PE( mgh or 1/2 Kx^2) + 1/2 mv^2 it is conserved in system involving only conservation forces its value never changes E is consatnt
an elastic collision of 2 objects characterized by the following
the total kinetic energy of the system remains constant AND the total momentum of the system is conserved
two metal spheres are made of the same material and have the same diameter but one is solid and the other is hollow. if their temp is increased by the same amount
the two spheres remain having an equal diameter
what is meant by the " heat death of the universe"
the universe will reach thermal equilibrium
floating means
the upward buoyant force EXACTLY equals the downward force
an arrow is shot into the air on a parabolic path to a target. at its highest point:
the upward component of velocity is ero BUT NOT THE ACCELERATION
at a given instant the acceleration of a certain particle is zero. this mean that
the velocity is not changing at that instant
snoopy is politing met life going aid his pal ..... in order to calculate the package snoopy must first determine
the velocity of the package with respect to the ground
a basketball is thrown toward the basket. at its highest point
the vertical component of the velocity is zero but not of the acceleration
when pressure is the same in a U shape tube
the water level is the same
the work energy theorem states that
the work done on an object is equal to the change in its kinetic energy
if outside agent does the work on an object the work is
the work is negative and the internal energy of the system INCREASES Q-(-W)= Q+w
which of the following statements expresses the relationship b/w the initial and final velocities for a projectile that is launched from and lands at the same level (x and y are the horizontal and vertical directions respectively)
the x component of the velocity is unchanged
which of the following statements express the relation b/w the initial and final velocities for a projectile that is launched from an....
the x component of the velocity is unchanged the y component of the velocity is equal in magnitude but opposite in diretion
WHICH OF THE FOLLOWING STATEMENTS IS A TRUE
the x-copoment of a vector is small that its y-component then that vector is in the opposite direction to its y-component
a lightweight object and a very heavy object are sliding with equal speeds along a level frictionless surface. they both slide up the same frictionless hill. which rises a greater height?
they BOTH slide to the same height
consider a hoop of radius R and mass M rolling without slipping. which form of kinetic energy is larger, transitional or rotational?
they are both equal
a solid and hollow sphere are released from rest at the same height and at the same time on inclined plane. they roll without slipping to the bottom and arrive at exactly the same time. we can conclude that
they have the same mass AND radius
2 children are riding a merry-go-round that is turning. child A sitting at a great distance from the axis of rotation than child B. which child has the larger angular displacement?
they have the same non-zero angular displacement
when pulling string outward the force points
to negative direction,
when pushing string inward the force point
to positive direction
averrage speed
total distance traveled over total elapsed time SI: m/s
an inelastic collision of 2 objects is characterized by the following:
total momentum of the system is conserved
consider a solid sphere (i=2/5MR^2) OF RADIUS R and mass M rolling without slipping. which form of kinetic energu is larger, translational or rational?
translational kinetic energy
forces cause
translational rotational : straight line
the statement an object cam move with constant instantaneous speed at the same time it can have a non-zero instantaneous acceleration is
true only if its direction of the object changes
Referring to the graph in problem #6 above, points A and E, and the line areas to the left of point A and to the right of point B are called
turning points, classically forbidden zones
2 athletes jump straight up. john has the initial speed of harry. compared to hard, john stays in the air.
twice as long
heat capacity C
unit in J/K or J/celsius tells you how much heat has to be put into or out of a thing to change its temperature alwas positive
buoyant Force
upward force exerted by a fluid on an object partly or completely immersed in it
2 identical planets with masses M and radii R are separated by distance "2d" A ROCKET WITH MASS m IS at rest midway between the planets. it is at rest distance d from the centers of the planets. fond the escape velocity
use equation: 2 radical (GM/d)
superposition
used to find the nET force isolate the body of interst and resolve each vector into its component and then adding them
P= F*V
used when object moving at constant speed traveling on AN INCLINEd surface at an angle above horizontal the object must exert a constant force F to equal the combined effects of friction gravity and air resistance
swimmers at a water park have a choice of 2 frictionless slides although both slides........ how does the speed V1 of a swimmer reaching the end of slide 1 compare with v2. the speed of a swimmer reaching the end of slide 2?
v1=v2
the speed v of a sinusoidal wave in deep water might depend on the wavelenght of the wave, which is the distance b/w 2 succesive wave crests, on the acceleration of gravity g, and on the density p(mass/volume) of the water . what's the equation
v= radical(g*wavelenght /2 pi)
on a level surface a bullet is fired at an angle theta above the horizontal with a speed v0. the horizontal distance covered by the bullet is give by the formula
v^2/g sin2theta
a car of mass m moving toward us with speed v , going around a curve of radius R on a road at an angle theta. if the road surface is very slippery so is offers no friction, the car can take the curve without sliding the speed obeys the formula
v^2=Rg Tan (theta)
Curve A is the figure is
van underdamped situation
when you multiply a vector by a scaler you get
vector
for an object in uniform circular motion its speed v is constant which is a correct description of the velocity v and acceleration a?
velocity is constant, acceleration is not constant
CLASSIFY THE FOLLOWING WAVES AS TRANSVERSE/ LONGItudinal/ both
water waves : both light waves : transverse sound waves in the air : longitudinal
what happen when you push a lawnmower
were exerting a force
what happen when you pick something
were exerting a force that equals the child's weight force
absolute ZERO
when all the molecules motion stops ZERO KELVIN
angular position
where Theta correspond to X = magnitude is measured from the reference line and is positive going counterclockwise, and negative going counterclockwise Theta is measured in radians
when bimetallic strip is heated, the strip bend toward the side
with the smaller coefficient of linear expansion
non-conservative forces
work done is lost forever : like friction and tension energy cannot be recovered , it got lost : heat
when we stretch or compress a spring the work is
work energy is always positive BUT THE WORK DONE MAY BE +/- DEPENDING ON SITUATIOn
if the inside does the work
work is POSITIVE an the internal energy if lowered Q-(+W)= Q-W
How can move Vectors
you can pick a vector and move it as long as THE MAGNITUDE AND DIRECTION are NOT changed
if the Force is greater than you weight
you feel heavier
if the force is less that your weight
you feel lighter
A satellite completes one full (circular) orbit around Earth. The work performed by Earth's gravitational force on the satellite is
zero j
