Explain why spectral lines are useful in determining the chemical composition of their source.

Question 9

One of the key early tests of Einstein's General Theory of Relativity was

the bending of the path of starlight and resulting apparent shift in the position of stars because of the Sun's mass.

sending a twin in a spaceship to the nearest star and back at a high Lorentz factor.

the Michelson-Morley experiment.

measuring the time dilation effect from gas falling into a black hole.

Question 10

According to General Relativity,

Group of answer choices

you can think of space as "flowing in" towards massive objects.

space-time has curvature.

time runs fastest far away from massive objects.

the path of light is bent when photons move through curved space.

All of these choices are correct.

None of these choices is correct.

Question 11

You are in a rocket ship deep in space and are about to pass a fellow traveler going the opposite direction at 99.9% the speed of light. You think her clock is _________ than yours and she thinks that your clock is __________ than hers.

faster; faster

faster; slower

slower; slower

slower; faster

Question 12

By observing a _____________ in 1919, astronomers were able to test the prediction that a massive object bends the path taken by light.

Group of answer choices

transit of the planet Mercury across the Sun

transit of the planet Venus across the Sun

supernova

total solar eclipse

total lunar eclipse

Question 13

The twin paradox is

a hypothetical experiment that demonstrates that special relativity is wrong

a hypothetical situation that seemingly presents a paradox but is actually resolved by a clearer understanding of the situation

a real experiment that demonstrates that special relativity is wrong

a real experiment that is consistent with the predictions made by special relativity

Question 14

Within special relativity, time dilation refers to ...

the slowing of the passage of time due to motion near the speed of light.

the speeding up of the passage of time due to motion near the speed of light.

the gradual slowing of the rotation of pulsars.

the Doppler shift of light.

Question 15

The alteration of our perception of space and time due to motion near the speed of light is described by

Group of answer choices

special relativity

general relativity

Newton's laws of motion

Galileo's law of inertia

Question 16

The curving of space by a massive object is described by which theory?

Group of answer choices

special relativity

general relativity

Newton's laws of motion

Galileo's law of inertia

You are measuring the distance between the 6th and 2nd levels of the hydrogen atom while it is passing you at 99.99% of c. ​

A) What will this distance appear to be in the direction perpendicular to the traveling speed. ​

B) What will this distance appear to be in the direction parallel to the traveling speed.​

Europa, a satellite of Jupiter, appears to have an ocean beneath its icy surface. Proposals have been made to send a robotic submarine to Europa to see if there might be life there. There is no atmosphere on Europa, and we shall assume that the surface ice is thin enough that we can ignore its weight and that the oceans are fresh water having the same density as on the earth. The mass and diameter of Europa have been measured to be 4.78×1022 kg and 3130 km , respectively

If the submarine intends to submerge to a depth of 70.0 m , what pressure must it be designed to withstand?

If you wanted to test this submarine before sending it to Europa, how deep would it have to go in our oceans to experience the same gauge pressure on Earth as the pressure at a depth of 70.0 m on Europa?

A child pulls on a wagon of mass 47 kg at an angle 33 degrees above the horizontal with a force of F. If the wagon accelerates at 3.7 m/s2 horizontally, what is the magnitude of the force F (in unit of N)? Assume there is coefficient of friction is 0.33, and please use g = 10 m/s2 to simplify computation.

A 4.0-kg block is on an incline plane of 30 degrees angle with respect to horizontal. a)What is the minimum coefficient of static friction (μ_s)_min is need to prevent it from sliding down? b) If the surface μ_s is 0.30, less than (μ_s)_min now, how much force(F) is needed to apply to the block horizontally to prevent it from sliding down?c) If F is doubled, what’s the acceleration of the block up the incline? Assume the coefficient of kinetic friction is 0.25.

On a horizontal frictionless surface, a small block with mass 0.200 kg has a collision with a block of mass 0.400 kg. Immediately after the collision, the 0.200 kg block is moving at 12.0 m/s in the direction 30

5. The mass of the sun is 2.00 x 1030 kg. The radius of the sun is 7.00 x 108 m.
a) What is the DENSITY of the sun?
b) What are the possible errors in your calculation in a)?
c) What is the PRESSURE at the center of the sun? (HINT: think of the sun as two
gravitation masses each 1⁄2 the mass of the sun at the radius of the sun apart.)
d) What are the possible errors in your calculation in c)?
e) What is the TEMPERATURE at the center of the sun? (HINT: use the "perfect gas
law" T = P (m/k) (1/r) where T = temperature in K0, P = pressure, m = mass of each
particle that makes up the sun (what do you think that is?), k = Boltzmann constant =
1.38 x 10-23 kg m2s-2 (K0)-1, and r is density. CHECK all your UNITS first!)
f) What are the possible errors in your calculation in e)?

4.15

A small 7.40-kg rocket burns fuel that exerts a time-varying upward force on the rocket. This force obeys the equation F=A+Bt2. Measurements show that at t=0, the force is 104.0N , and at the end of the first 1.50s , it is 193.0N .

Find the constant A

Find the constants B

Find the net force on this rocket the instant after the fuel ignites.

Find the acceleration of this rocket the instant after the fuel ignites.

Find the net force on this rocket 4.90s after fuel ignition.

Find the acceleration of this rocket 4.90s after fuel ignition.

Suppose you were using this rocket in outer space, far from all gravity. What would its acceleration be 4.90s after fuel ignition?

Explain the difference between homogeneous and inhomogeneous broadening and give an example of a broadening mechanism for each of the two cases.

The wall of a house is made from a layer of wood 3cm thick and a layer of wool which is 5.3 cm thick. The layer of wood faces outside and the layer of wool faces inside. The thermal conductivity of wood is 0.08W/mK and the thermal conductivity of wool is 0.02W/mK. The temperature outside the house is 0^oC and the temperature inside the house is 19.8 ^oC. What is the temperature (in ^oC) at the contact surface between the wool and the wooden layers?

A spring constant of 250.0 N/m is suspended vertically with its upper end fixed to the ceiling and its lower end at position y=0.000 cm. A block of weight 25.0 N is attached to the lower end, held still for a moment and then released. What are the kinetic energy changes and the changes from initial values in the gravitational potential energy of the spring-block system when the block is at values of y equal to (a) -5.00 cm (b) -10.0 cm (c) -15.0 cm (d) -20.0 cm? Tabulate your results, Include units at the top of each column.

7. A single photon, from an unpolarized source, traveling in the z direction is directed through a series of three polarizers: first a polarizer with its axis in the x direction, then a polarizer at 25 degrees to the x direction, then finally a y polarizer.

a) What is the probability that the photon makes it through the first (x) polarizer and what is the photon’s polarization after it comes through the first polarizer?

b) For a photon that got through the first (x) polarizer, what is the probability that that photon goes through the next two polarizers and what is the photon’s polarization after it comes through the last polarizer?

c) If the middle (25 degree) polarizer is removed, what is the probability that the photon gets through both (remaining) polarizers?

Bob lifts a 0.9kg cup of coffee, initially at rest on the table, up to his mouth. The cup comes to rest after a vertical displacement of 0.7m. (NO IMAGE GIVEN)

a. In the process of being lifted, how much work was done on the cup by Bob?

b. Bob then hold the cup stationary for 1.8s. How much work was done on the cup by Bob during this time?

c. Realizing that the cup is empty, Bob lowers the cup 1.1m downward into the sink, where it comes to rest. How much work was done on the cup by Bob in the process of being lowered?

A. What is the moment of inertia of a solid iron sphere 20 inches in diameter about an axis passing through the sphere half way from its center to the surface (you will have to look up its density)? If the sphere rolls down an incline plane that makes an angle 20 degrees with the horizontal, what will be its acceleration?

B. Derive the formula for acceleration of a circular disk that rolls down an inclined plane that makes an angle θ with the horizontal. (draw a diagram and say in words what you are doing)