The Frontiers of Matter (in 1932) - University of Richmondggilfoyl/genphys/131/slides/quark… · The Frontiers of Matter (in 1932) The periodic chart orders the chemical elements

The Frontiers of Matter (in 1932)

The periodic chart orders thechemical elements accordingto their properties.It provides clues to the un-derlying atomic structure.The ‘fundamental particles’of the periodic chart are theatoms/elements themselves.

What are the atoms/elements made of?

Protons and neutronsWhat are the protons and neutrons made of?

Quarks and gluons

Jerry Gilfoyle Hunting for Quarks 1 / 36



What are the atoms/elements made of? Protons and neutrons

What are the protons and neutrons made of?

Quarks and gluons




What are the atoms/elements made of? Protons and neutronsWhat are the protons and neutrons made of?

Quarks and gluons




What are the atoms/elements made of? Protons and neutronsWhat are the protons and neutrons made of? Quarks and gluons


The Frontiers of Matter (now)

The Universe is made ofquarks and leptons andthe force carriers.

The atomic nucleus is madeof protons and neutrons boundby the strong force.

The quarks are confined insidethe protons and neutrons.Protons and neutrons are NOT confined.


Setting the Quarks Free

Despite quark confinement there is a way to get them out of the proton orneutron. Hit a quark hard enough with something small like an electronand if it is immersed in nuclear matter, the tug of the nearby protons andneutrons cancels some of the forces on the struck quark. We’ll model thisstruck quark as a particle moving through the nucleus bound to it originalpartners by a string that exerts a constant force. Does the quark make itout of the nucleus?

RPb

Lead nucleus

Incoming electron

Target quark confined to a proton

bv

Quark string

Scattered electron

Struck quark

vo = 3× 108 m/s|a| = 4× 1030 m/s2

b = 3.0× 10−15 mRPb = 7.1× 10−15 m


One-Dimensional Motion

time (t)

positio

n(x)



A

B

time (t)

positio

n(x)



Δt

A

B

time (t)

positio

n(x)



Δx

Δt

A

B

time (t)

positio

n(x)



Δx

Δt

A

B

time (t)

positio

n(x)



A

B

Δt

time (t)

positio

n(x)



A B

Δt

time (t)

positio

n(x)



A

B

Δt

time (t)

positio

n(x)



A

B

Δt

time (t)

positio

n(x)



A

B

Δt

time (t)

positio

n(x)



Tangent line

A

B

Δt

time (t)

positio

n(x)



A

B

A BA

B

A

B

A

B

Tangent line

time (t)

positio

n(x)



An elevator in the world’s tallestbuilding, the Burj Dubai in Dubai,United Arab Emirates, is mov-ing and its vertical position is de-scribed by the following equation

x(t) = A+ Bt + Ct2

where A = 5.0 m, B = 2.1 m/s,and C = −4.9 m/s2. What is theinstantaneous velocity at any timet? What is the average velocitybetween two times t0 = 0.0 s andt1 = 1.0 s?


Position and Velocity


Captain Kirk’s Bad Day

The starship Enterprise has lostpower and is plunging straight intothe heart of a black hole. Its velocityas a function of time is described by

v(t) = F + Gt

where F = 2.0 × 107 m/s and G =9.0× 1010 m/s2.

What is the instantaneous accelera-tion?

Do the velocity and acceleration ver-sus time plots make sense?


Catching Up

At the instant a traffic light turns green, a ‘car’ starts with a constantacceleration a = 2.2 m/s2. At the same instant a truck is 5.0 m behindthe car and traveling with a constant speed vt = 9.5 m/s. How far doesthe car travel before overtaking the truck? What do the position versustime plots look like for the car and the truck?

Car

Truck

time (t)

Positio

n(x)


Catching Up

At the instant a traffic light turns green, a ‘car’ starts with a constantacceleration a = 2.2 m/s2. At the same instant a truck is 5.0 m behindthe car and traveling with a constant speed vt = 9.5 m/s. How far doesthe car travel before overtaking the truck? What do the position versustime plots look like for the car and the truck?

Car

Truck

time (t)

Positio

n(x)


EEEEKKK!!

Two trains, one traveling at 20 m/s and the other at 40 m/s, are headedtoward one another along a straight, level track. When they are 950 mapart, each engineer sees the other’s train and instantly applies the brakes.The slow-moving train stops. The brakes decelerate each train at a rate of1.0 m/s2. Is there a collision? If so, how long after the brakes are applied?


EEEEKKK!!

Two trains, one traveling at 20 m/s and the other at 40 m/s, are headedtoward one another along a straight, level track. When they are 950 mapart, each engineer sees the other’s train and instantly applies the brakes.The slow-moving train stops. The brakes decelerate each train at a rate of1.0 m/s2. Is there a collision? If so, how long after the brakes are applied?


Don’t Do This At Home

A window washer named Chris Sag-ger is reported to have fallen (as-sume starting from rest) 67 metersfrom a building where he was work-ing, landed on a car, and lived. Sup-pose the roof of the car was com-pressed 1.45 m. Ignoring air resis-tance what is his speed just beforehitting the car? Treating his accel-eration as constant, how long did ittake him to come to a stop after hemade contact with the box? Whatwas his acceleration?


Measurement and Uncertainty

True value

Same number of

measurements with

different standard

deviations Same average

x

Nu

mb

er

of

Me

asu

rem

en

ts

Average and Standard Deviation


Precision versus Accuracy

Not precise. Precise, but not accurate. Precise and accurate.

True value

x

Nu

mb

er

of

Me

asu

rem

en

ts


True value

x

Nu

mb

er

of

Me

asu

rem

en

ts


True value

x

Nu

mb

er

of

Me

asu

rem

en

ts



Understanding some Statistics

x

Nu

mb

er

of

Me

asu

rem

en

ts




True value

σ σ

x

Nu

mb

er

of

Me

asu

rem

en

ts




True value

σ σ68% of area

x

Nu

mb

er

of

Me

asu

rem

en

ts



Does the quark escape?An electron strikes the quark bound inside a proton that is a constituent ofa lead nucleus in the configuration shown in the figure. The quark is nearthe surface of the nucleus. The collision gives the quark an initial velocity~vo and an acceleration ~a as it moves through the nuclear medium. Seebelow for numbers. Does the quark make it out of the nucleus?

vo = 3× 108 m/s|a| = 4× 1030 m/s2

b = 3.0× 10−15 mRPb = 7.1× 10−15 m

RPb

Lead nucleus

b

Struck quark

v0

x

y


Does the quark escape?An electron strikes the quark bound inside a proton that is a constituent ofa lead nucleus in the configuration shown in the figure. The quark is nearthe surface of the nucleus. The collision gives the quark an initial velocity~vo and an acceleration ~a as it moves through the nuclear medium. Seebelow for numbers. Does the quark make it out of the nucleus?

vo = 3× 108 m/s|a| = 4× 1030 m/s2

b = 3.0× 10−15 mRPb = 7.1× 10−15 m

RPb

Lead nucleus

b

Struck quark

v0

x

y


Turning Around 1


Position and Velocity


Changing Motion


Changing Motion


Changing Motion


Turning Around 1


Turning Around 2


Turning Around 3


Personal Information

Name:

How many semesters of physics?

How many semesters of calculus?

Preferred personal pronouns?


The Frontiers of Matter (in 1932) - University of Richmondggilfoyl/genphys/131/slides/quark… · The Frontiers of Matter (in 1932) The periodic chart orders the chemical elements

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