The uncertainty principle arises from a common-sense idea: To measure something, you must affect it somehow. For instance, when you use a pressure gauge to measure air pressure in a car tire you release a small amount of air into the gauge.

• When you shine a light on an object, the momentum from the photons that make up that light impacts the object. For macroscopic objects, this will have no measurable effect. Describe why this is different for atomic-sized objects.
• Suppose you shine a very long wavelength light on one electron and a very short wavelength light on another electron. What differences will you observe?
• Why does shining very short wavelength photons on an electron not tell you exactly where the electron is?
• Describe two other examples of situations in which measuring something about an object somehow changes it.

Land footprint of solar energy:

(a) In 2016, Arizona’s total annual electricity consumption was 78.05 million MWh. What is this in terms of kWh per day?

(b) Land footprint: The average daily insolation in Phoenix is 5.38 kWh/m2/day. Given this daily energy input, how much land area would you need (in square miles) to generate all of Arizona’s daily electricity from the following types of PV panels:

i. Mono-crystalline Si panels with an efficiency of 22 %?

ii. Thin film CdTe with an efficiency of 12%?

(c) Translate to rooftops: Assuming we use 22% efficient mono-crystalline Si panels, how many rooftops would that take if we put the panels on:

i. Wal-Mart stores with an average size of 102,000 square feet?

ii. Household rooftops with an average size of 2,000 square feet?

(d) Reflection: These types of crude statistics get used all the time in public debates about solar energy. Do you think they’re useful? Why or why not? Take about 3-4 sentences to explain what we learn from this exercise and whether you think it’s useful for talking about solar energy.

The figure below is a section of a conducting rod of radius R1=1.30mm and length L=11.00m inside a thick-walled coaxial conducting cylindrical shell of radius R2=10.0R1  and the (same) length L. The net charge on the rod is Q1=-4.30∗10−12C that on the shell is Q2=-4.00Q1.

a) What is the magnitude E of the electric field at a radial distance of r = 2.50R2?

b) What is the direction of the electric field at the radial distance (inward, outward, or zero)? Give reasons!

c) What is the magnitude E of the electric field at a radial distance of r = 3.60R1?

d) What is the direction of the electric field at that radial distance (inward, outward, or zero)? Give reasons

1. What is ductile fracture? What is brittle fracture? (10 pts) 8. Please describe the differences between ductile fracture and brittle fracture. (10 pts)

A stone is dropped from the roof of a building, 1.10s after that a second stone is thrown straight down with an initial speed of 20.0 m/s & the two stones land at the same time

How high is the building h=???m

What is the direction of the magnetic field of a straight, current-carrying wire?

A mass spectrometer is being used to separate common oxygen-16 from the much rarer oxygen-18, taken from a sample of old glacial ice. (The relative abundance of these oxygen isotopes is related to climatic temperature at the time the ice was deposited.) The ratio of the masses of these two ions is 16 to 18, the mass of oxygen-16 is 2.66 × 10-26 kg, and they are both singly charged and travel at 4.9 × 106 m/s in a 1.45 T magnetic field.

What is the separation between their paths in meters when they hit a target after traversing a semicircle?

Δd =

consider the neon atom in all possible n+1, l-1 excited states that relax down to the ground state and emit light in the process. (a) Write the atomic term symbol for each of these states including the ground state (hint, use the Clebsch-Gordon series, there should be 8 total term symbols). Show your work in how you arrive at these term symbols. (b) Draw an energy level diagram showing decay of these states to the ground state by listing them in the proper order of there energies and indicate which states are allowed transitions by using an arrow to show the decay of energy from one state to the next. This is a qualitative exercise, no need to look up the values or draw the energy levels accurately - just the proper order of energy will suffice.

Suppose the length of a clock's pendulum is changed by 1.000%, exactly at noon one day. What time will it read 24 hours later, assuming it kept perfect time before the change? Note that there are two answers, and report your answers to the nearest second. Be sure to keep track of extra sig figs.

a)An object of mass ?m rests on a horizontal frictionless surface. A constant horizontal force of magnitude ?F is applied to the object. This force produces an acceleration:

• always
• only if ?F is larger than the weight of the object
• only while the object suddenly changes from rest to motion
• only if ?F is increasing

choice A

b)Now let there be friction between the surface and the object. If the object has a mass of 10 kg, and ??μs = 0.4, and ??=0.3μk=0.3, how much force would be required to cause the object to move?

c)If this force is then applied continuously, how far will the object be displaced after 4.8 seconds?

d)How fast will it be going after pulling with the same force above for 4.8 seconds?

What would be the acceleration voltage that we have to apply in the e/m ratio apparatus, when the current in the Helmholtz coils is equal to 2 amp, to achieve a radius of 5 cm of the circle of the electron path? Turns per Coil, N=132. Coil Radius, a=147.5mm.

Reference : Physics for Scientist and Engineers Chapter 21.

Two point charges q1 = 2 C and q2 = - 5 C are located in the (x,y) plane at coordinates (2,0) m and (-3,0) m respectively. Find:

a) The electric field created for both charges at points (0,0), (5,0) and (0,2)

b) the electric force on a point charge of -2.00 C placed at points (0,0), (5,0) and (0,2)

Have you ever ridden a free-fall ride at an amusement park, where the riders are suspended at a terrifying height and then plummet towards the ground in free fall? These rides use a Lenz’s law mechanism to slow the drop. Explain how Lenz’s law applies to this situation and why this mechanism is ideal for such an application.

Show that energy is conserved in a simple charging RC circuit. That is show that the total work done by the battery equals the final energy stored in the capacitor plus the energy dissipated in the resistor.

Proposition.

You and your friends are learning to play hockey, and you decide to use physics to get better by analyzing your movements. You are skating directly towards your friend at (5.98, 0) M/S who is also skating directly towards you to get the puck at a constant velocity of (-2.7, 0) M/S, and both of you reach the puck at the same time, so you collide and stick together. At the same time your hockey helmet with a mass of 5 kg goes flying away with a velocity of (0, 2.68) m/s. You have a mass of 74 Kg, your friend has a mass of 68 kg.

The questions:

1) In vector form, what is you and your friends velocity after you collide?

2) after the collision the puck is not moving on the ice and another player hits the puck towards the goal. If the average hockey player can apply a force of 80N over a 0.1s time and the goal is 15m away then provide evidence of whether or not the puck will reach the goal. the frictional force a puck experiences is 10N and the mass of a puck is .25kg. Consider friction in this case since the puck is made of a rough material.

Please show all work and explain why you are using the equations you are using !! Thank you so much. My physics teacher doesn't teach at all.