A loaded truck of mass 3000 kg moves on a level road at a constant speed of 6.000 m/s. The frictional force on the truck from the road is 1000 N. Assume that air drag is negligible. (a) How much work is done by the truck engine in 10.00 min? (b) After 10.00 min, the truck enters a hilly region whose inclination is30∘and continues to move with the same speed for another 10.00 min. What is the total work done by the engine during that period against the gravitational force and the frictional force? (c) What is the total work done by the engine in the full 20 min?

1. A 170 g copper bowl contains 110 g of water, both at 23.0°C. A very hot 370 g copper cylinder is dropped into the water, causing the water to boil, with 4.17 g being converted to steam. The final temperature of the system is 100°C. Neglect energy transfers with the environment. (a) How much energy is transferred to the water as heat? (b) How much to the bowl? (c) What is the original temperature of the cylinder? The specific heat of water is 1 cal/g·K, and of copper is 0.0923 cal/g·K. The latent heat of vaporization of water is 539 Cal/kg.

2. One liter of a gas with γ = 1.30 is at 369 K and 1.98 atm pressure. It is suddenly compressed adiabatically to 1/9 its original volume. (a) Find its final pressure and (b) temperature. (c) The gas is now cooled back to 369 K at constant pressure. What is its final volume?

What are the limitations of forward-bias, if any, on a semiconductor diode?

What are the limitations of reverse-bias, if any, on a semiconductor diode?

What portion, if any of the volt-ampere characteristic of the diode (when it is forward-biased) is linear?

What can you say about the d-c resistance of the diode over this linear portion?

3) You are working with a lab instrument that has a diffraction grating of 600lines/mm. 450nm wavelength light passes through the grating and hits a screen 2m away from the grating.

a. What is the spacing between the lines of the grating? b. Given this spacing, what is the distance between two bright spots on the screen? c. If you instead send red (650nm) light through the screen, would this increase or decrease the spacing on the screen? Find the distance between two bright spots with red light.

A bicycle racer sprints at the end of a race to clinch a victory. The racer has an initial velocity of 11.2 m/s and accelerates at the rate of 0.3 m/s2 for 6.9 s.

a)The racer continues at this velocity to the finish line. If he was 293 m from the finish line when he started to accelerate, how much time did he save (in s)?

b)One other racer was 5 m ahead when the winner started to accelerate, but he was unable to accelerate, and traveled at 11.5 m/s until the finish line. How far ahead of him (in seconds) did the winner finish?

c) How far ahead of him (in meters) did the winner finish?

A fast elevator in a skyscraper is employing the following scheme to get from the starting level to the desired level: For the first half of the time it accelerates at the maximum allowed acceleration of 1.0 m/s2 and for the second half it decelerates at the maximum allowed acceleration of −1.0 m/s2. How long does it take (in seconds) to go from ground level to the highest level at 80 m elevation?

A track team is practicing for a 4 × 100 m relay race. The first runner, Linda, is running at a constant speed of 8.6 m/s. The next runner, Jenny, will be starting from rest at the 80 m mark. She has an acceleration of 1.0 m/s2. Ideally the two runners meet at the 100 m mark to hand over the baton. At this point, Jenny is still accelerating.

a) How long does it take Jenny to run from the 80-m mark to the 100-m mark?

b) At what distance behind Jenny should Linda be when Jenny starts running? (Assume for simplicity that there is no distance between the two runners when the switch happens.)

c) What’s Jenny’s speed at the 100m mark?

An electric current passes through a metal strip 0.50 cm by 5.0 cm by 0.10 mm, heating it at a rate of 128 W. The strip has emissivity e=1 and its surroundings are at 306 K. What will be the strip’s temperature(K) if it’s enclosed in an insulating box with thermal R=12 K/W resistance that blocks all radiation?

Set the focal length of the converging lens to 3.0 cm and the object height 2.0 cm.

1. Start with the object distance at 8.0 cm. What happens to the image position and image height as the object distance is increased to 10.0 cm?
2. What happens to the image position and image height as the object distance is decreased to 6.0 cm?

3. Next we’ll investigate images formed when the object is closer to the lens than the focal point. Set the focal length of the converging lens to 8.0 cm, the object position to 0 cm, and object height to 2.0 cm. Do the rays cross at a point after passing through the lens? What do the rays do on the right side of the lens (that is, after passing through the lens)?

Tiny dust particles are attracted to static charges, so if you could get them from the motor to the air intake by the floor, it may help to pick up even more dust. What could you do to get the static from the motor to the floor attachment? Explain your reasoning.

7) a) What is the energy emitted in 1 minute from a black coffee mug which has a radius of 4 cm and height 6 cm and temperature of 70 Fahrenheit. What will the answer be if the coffee mug is at 200 Fahrenheit?

b) Now, assume the mug is completely filled with creamed coffee. Assume both of their temperatures are initially at 200 Fahrenheit and the atmospheric temperature is 70 Fahrenheit. How long will it take each one to reach 71 F ignoring the transfer of heat to each other by conduction? (Take the density of the coffee to be 1.1 g/cm3 , its specific heat to be .95 cal/g.C and the mass of the cup to be 200 grams and its specific heat to be .4 cal/g.C. Also, take the emissivity of the creamed coffee to be .3)

what is the wavelength of thermal neutrons? what "type" of light would this correspond to (X-ray, UV, VIS, IR)?
hint: a thermal particle has an average kinetic energy of ekin=3/2 KT with KT= 25 meV. m(neutron) = 1.674x10^-27 kg.

please answer with short verbal comment
you notice that the probability Pab(t) of finding a particle between a<x<b at time t (gaussian wave packet function) changes with time. does this mean that the particle self-destructs?

Write down the four Maxwell Equations (Work on your OWN)

a. Explain them. What do they do, how are they used? What are their applications.

b. Write an example question for each of the Maxwell equations and Solve them.

Suppose that we have a reservoir that has a surface area of 50 acres, with an average depth when full of 15 meters. [Conversion: 1 acre = 4096.86 square meters] If the reservoir were to start out with a depth of 0 meters and eventually be filled to a depth of 15 meters, (1) how much volume of water will have been added in the filling of the reservoir from 0 meters depth to 15 meters depth?

(2) What mass of water does this added volume of water have?

(3) How much potential energy increase takes place when all this water was raised from a river at an average elevation of 200 meters so that the water in the upper reservoir has an average elevation of 300 meters. (Note: For simplicity, just take the height change of the water to be 100 meters from the river to the reservoir, thus neglect that some water moves from the river to a slightly different heights as the surface of the reservoir rises. This is what was meant by saying the water in the upper reservoir has an average elevation of 300 meters.)

(4) How much power will be available to a city from the reservoir if 2 % of the water (i.e., stored energy) in the full reservoir is drained in ½ hour through the turbine that generates electricity? To help to provide context for the answer you will get, there is a power plant located at Mt. Tom Junction (which you can see if you travel south on route 91 near where Easthampton meets Holyoke). It was recently decommissioned, but used to burn coal (1200 tons per day) to create steam to spin turbines to generate electricity and had an advertised power production capacity of 146 megawatts (mega = million). Such a water storage arrangement can be used to quickly supplement such a power plant when the needs for energy fluctuate, or when there is short-term high demand. This plant used to be able to provide more than twice the needs of the city of Holyoke.

On this related web site, (http://www.northfieldrelicensing.com/Pages/Northfield.aspx ) note that the specifics of the energy storage system used by this power plant at its Northfield site are similar to the case we have calculated here. (5) On that site, see how many megawatts of power (Powerhouse section - historic station capacity) can be delivered by the Northfield reservoir when the water flows down through a total of four turbines. What is that number? Be careful to get your number from the section of the web page that mentions the four turbines and the historic capacity.

Now this Mt. Tom power plant used to use 1200 tons of coal per day to create 146 megawatts of power. As noted, the coal is burned, heats water to make steam, the steam turns turbines and electricity is generated. Other things can turn turbines. For example, a windmill has a set of blades that cause the shaft to which they are attached to turn when the wind blows. This shaft turns a turbine and that generates electricity. Let’s take a look at a farm of such windmills. There is an approved project to create a windmill farm off the coast of Cape Cod in Nantucket Sound. It is said that the windmill farm will generate 1,491,384 megawatt hours of energy per typical year. Recall that the kilowatt hour is a unit of energy. So is the megawatt hour, it is just bigger.

(6) So, how many joules of energy will this be per year? That fossil fuel power plant at Mt. Tom Junction produced 146 Megawatts of power.

(7) If it did this continuously for one year, how may joules of electrical energy could the coal-burning Mt. Tom power plant produce over the entire year?

(8) Compare this number with the one you got for the wind farm. Is the number roughly comparable? Here is a web site that talks about how much carbon dioxide is created when a ton of coal is burned. (http://wiki.answers.com/Q/How_much_carbon_dioxide_does_a_ton_of_coal_produce)

(9) Look at that site, presume that the Mt. Tom power plant burned bituminous coal (as opposed to some other kind), and compute how many pounds of carbon dioxide per year were introduced into the atmosphere by the Mt. Tom coal-fired power plant. Wind farms that replace coal-fired power plants help reduce greenhouse gasses (carbon dioxide). Just as a comment: a maple or birch tree that is 25 years old will absorb about 3 pounds of carbon dioxide from the atmosphere per year, but this depends on the type of tree. A 25 year old white or red pine will absorb about 14 pounds per year. Deforestation in various places eliminates the natural ability of such trees to clean the atmosphere. Take a look here http://wiki.answers.com/Q/Co2_consumption_by_rain_tree if you want more information (optional). To get a rough idea about personal energy use and the carbon dioxide emission that results, check out this nice little calculator and try to enter some values: http://www.carbonify.com/carbon-calculator.htm. Note that in the calculator some unstated assumptions are made, but it is a useful exercise. So, for example, using the calculator:

(10) If you drive an average medium sized car and drive 600 miles per month, how many tons of carbon dioxide do you put into the atmosphere per year? (Hit enter after you put 600 in the box for an average car.)

(11) At the bottom of the calculator, read off how many average trees are needed to offset this driving and reabsorb the carbon dioxide. As another example, my house typically requires about 1400 gallons of heating oil over the year.

(12) Use the calculator to determine how many tons of carbon dioxide this oil use puts into the atmosphere each year. (Be careful to note that the calculator quantity column is in terms of per month.)

Two warlords aim identical catapults (i.e. they both release rocks at the same speed) at each other, with both of them being at the same altitude. The warlords have made the necessary computations to crush the other and fire their catapults simultaneously. Amazingly, the two stones do not collide with each other in mid-air, but instead, the stone Alexander fired passes well below the stone that Genghis shot. Genghis is annihilated 8.0s after the catapults are fired, and Alexander only got to celebrate his victory for 4.0s before he too was destroyed. Find the amount of time that elapses from the launch to the moment that the rocks pass each other in the air.