This

**preview**shows pages 1-2. to view the full**6 pages of the document.**PHY100

December 16, 2008

Final Exam Name:

Aran Garcia-Bellido

Please read the problems carefully and answer them in the space provided. Write on the back

of the page, if necessary. Show your work where requested in order to be considered for partial

credit. In problems where you are requested to show your work, no credit will be given unless

your work is shown.

Potentially useful formulas:

F=Gm1m2

r2

F=kq1q2

r2

F=ma

Distance = Speed ×Time

v=∆x

∆t

a=∆v

∆t

Momentum = p=mv

Length contraction (space is longer in proper frame) : L′=γL

Time dilation (time is shorter in proper frame) : T=γT ′

γ=1

p1−(v

c)2

Wave properties : v=λν ;ν= 1/T (T = period)

Energy of a particle/wave : E=hν

De Broglie matter waves : λ=h

p=h

mv

Uncertainty principle : ∆x∆p>h ; ∆E∆t > h

Constants : c = 300,000 ×103m/s ; G = 6.67 ×10−11 Nm2

kg2

k = 9 ×109Nm2

C2; h = 6.6×10−34 Js

g=GM

r2= 9.8 m/s2(in the surface of the earth)

Do not forget to put units in your results!

(4pts)

4 pts

1. When we speak of the ”spectrum” of a radiation source, we are referring to

(a) the set of discrete velocities that its particles actually have

(b) the various types of atoms and molecules of which the source is composed

(c) the set of frequencies that the source can emit when electrons make transitions between atomic

orbitals

(d) the various frequencies at which its particles collide with each other

(e) the inherent motion of the electrons in the atomic orbitals

4 pts

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

PHY100/Final Exam – Page 2 of 6 – Name:

(6pts)

6 pts

2. Show your work. A car has a mass of 1000 kg.

(a) (2 pts) How much does the car weigh?

If this car is traveling along a straight level road powered by a forward drive force of 500 N, the force

of air resistance is 200 N, and rolling resistance is 100 N.

(b) (2 pts) What is the net force on the car, and in what direction?

(c) (2 pts) What is the car acceleration?

(8pts)

8 pts

3. Is intergalactic space empty? Defend your answer from what you know about cosmology and quantum

physics.

14 pts

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