explain why it makes some sense that a large temperature difference enables greater efficiency.

A 4100 kg open railroad car coasts along with a constant speed of 9.90 m/s on a level track. Snow begins to fall vertically and fills the car at a rate of 5.00 kg/min . Ignoring friction with the tracks, what is the speed of the car after 80.0 min ?

An alpha (?) particle is the nucleus of a 4He atom and consists of 2 neutrons and two protons bound together. Let's take apart an ? particle, step by step, looking at the energy required at each step. To do so, we may want to use the following atomic masses: 4He 4.0026 u 2H 2.0141 u 3H 3.01605 u 2H 1.00783 u p 1.00728 u n 1.00867 u e 5.48

two cylinders with the radius r= 0.650 m are rolled with out slipping down an incline that desends a vertical distance of 2.45 meters each cylinder has equal mass m=3.68kg but one is solid the other is hollow shell

a) what is the center mass velocity of the solid cylinder at the bottom of the incline

b) what is the center mass velocity of the holllow cylinder of the botom of the incline

c) what is the angular frequency of each cylinder when it reaches the bottom of the incline

Neutron Decay 4 On their own, neutrons are unstable particles with a half-life of 618 s when at rest. They decay into a proton, an electron and an electron antineutrino. Half-life is the time that it takes half of a collection of unstable particles to decay.

a- The highest energy neutrons produced in a nuclear reactor are traveling at about %15 of the speed of light, About how many seconds is longer in this half - life for these neutrons?

b . If a bunch of high energy neutrons is emitted from the sun at about 0.88c and travels to earth , some 150 million km away , will more than half or less than half of the neutrons make it to earth before turning into protons ? Show how you reached your conclusion

A doughnut contains about 302 Calories. (Note: These are "food" Calories.) After eating this doughnut, you decide to compensate by taking the stairs instead of using the elevator. If each stair has a height of 22 cm, how many stairs must you climb to compensate for the doughnut? Assume all the energy in the doughnut can be converted to mechanical energy. (Take 75 kg as the mass of a typical person.)

A mass m = 78 kg slides on a frictionless track that has a drop, followed by a loop-the-loop with radius R = 15.4 m and finally a flat straight section at the same height as the center of the loop (15.4 m off the ground). Since the mass would not make it around the loop if released from the height of the top of the loop (do you know why?) it must be released above the top of the loop-the-loop height. (Assume the mass never leaves the smooth track at any point on its path.)

What is the minimum speed the block must have at the top of the loop to make it around the loop-the-loop without leaving the track?

What height above the ground must the mass begin to make it around the loop-the-loop?

If the mass has just enough speed to make it around the loop without leaving the track, what will its speed be at the bottom of the loop?

If the mass has just enough speed to make it around the loop without leaving the track, what is its speed at the final flat level (15.4 m off the ground)?

Now a spring with spring constant k = 1.8 × 10⁴ N/m is used on the final flat surface to stop the mass. How far does the spring compress?

It turns out the engineers designing the loop-the-loop didn’t really know physics – when they made the ride, the first drop was only as high as the top of the loop-the-loop. To account for the mistake, they decided to give the mass an initial velocity right at the beginning.

How fast do they need to push the mass at the beginning (now at a height equal to the top of the loop-the-loop) to get the mass around the loop-the-loop without falling off the track?

The work done by the normal force on the mass (during the initial fall) is:

1. A vibrating string is cut in half. The fundamental frequency of the string will be...

a. doubled

b. unchanged

c. reduced by half

2.On a pipe organ, for a closed pipe, if you double the length of the pipe, what happens to the fundamental frequency?

a. It does not change.

b. It doubles.

c. It is reduced by half.

d. It is reduced by 1/4.

e. It is increased 4x.

3. When you blow gently across the top of a particular soda bottle, it emits a tone. The column of air in the bottle is vibrating up and down in its fundamental mode. If you replace the air in the bottle with something heavier than air (like carbon dioxide) and then blow gently across the top of the bottle, it will emit

a) a higher pitched tone. b) a tone at the same pitch as before.

c) no sound at all. d) a lower pitched tone.

9. If you blow across the top of a half full bottle of soda you can produce a clear tone. If you take a drink of soda to reduce the amount of liquid in the bottle and try this again the pitch (frequency) of the sound produced will

a) increase. b) stay the same.

c) exactly double. d) decrease.

An ac generator has a frequency of 7.5 kHz and a voltage of 35 V. When an inductor is connected between the terminals of this generator, the current in the inductor is 30 mA. What is the inductance of the inductor?

An energy saving lamp with a power of P = 11 W emits an electromagnetic wave uniformly in all directions. Calculate the wave at a distance of r = 3 m from the lamp

(a) the intensity

(b) the radiation pressure

(c) electric field amplitude

(d) the amplitude of the magnetic field

What are probable healt effects of:

• Ozone
• Partiuclate matter
• Sulfur Oxide
• Lead
• Carbon Monoxide
• Nitrogen Dioxide

To children, average adults, and the elderly??

(include your sources)

A mysterious tower has been constructed at the edge of a gridiron football field. Even more mysteriously, the field has been marked carefully in meters instead of yards. On top of the tower is a well calibrate ball launcher that will fire heavy ball at a velocity of 14.7 m/s at an angle of 20 degrees abive the horizontal. The ball lands 46.1 meters away from the base of the tower.

A) How long does it take for the ball to reach max height?

B)How long does it take for the ball to return to the height from which it was launched?

C) What is the total flight time of the ball?

D) How tall is the tower?

Please explain the contiguity of spacetime?

A magnetic field is along the xy plane and the z plane is perpendicular to the magnetic field. In which plane(s) is the magnetic flux the greatest? Please explain.

At t = 0s, the leading edge of a wave (wavelength 1m) is 3m to the left of a boundary. The wave is moving to the right at 1m/s. The transmitted wave has wavelength 3m. (You may draw pictures to help you answer the questions below, but you must explicitly state - in words - the answers to the questions.)

(a)[8 pt(s) ]At t = 5s, where is the leading edge of the transmitted wave? Is the transmitted wave inverted or non-inverted, and why?