A cylindrical metal can, 0.1 m high and 0.05 m in diameter, contains liquid helium at its normal boiling point of -452.074 degrees Fahrenheit. At this temperature Helium's heat of vaporization is 20.4 kJ/kg. The walls of the helium container are 1.2 cm thick and have a thermal conductivity of 13.889 W/(m K). The helium container is surrounded by liquid nitrogen at a temperature of -327.64 degrees Fahrenheit.

A. What is the conductive surface area of the metal cylinder?

B. What is the temperature of the liquid helium in Kelvin?

C. What is the temperature of the walls in Kelvin?

D. What is the rate of heat flow into the Helium due to the conduction?

E. How much Helium is lost per hour due to conduction?

Two stationary positive point charges, charge 1 of magnitude 3.55 nC and charge 2 of magnitude 2.00 nC , are separated by a distance of 53.0 cm . An electron is released from rest at the point midway between the two charges, and it moves along the line connecting the two charges.

What is the speed v final of the electron when it is 10.0 cm from charge 1?

A 1.80 x 10^-3 kg coin is on the outer-most edge of a spinning turntable, which has a radius, r, of 0.250 m.

μ_s for the coin-turntable interface is 0.690.

1) The speed at the edge of the turn table is increased until the coin just starts to slide.This maximum speed, v_max , in m/s is:

2) If the period is held constant when v_max is reached and the coin is moved halfway between the center of the turntable and the turntable's outer edge, the coin will have a higher speed and will be less stable. True or False

3) The period, T, for a coin on a turntable is the same at the outer edge as it is at the halfway point. Similarly, as the earth spins on its axis, the period that a person experiences in Seattle is the same as it is at the equator and relative to the universe the period is about 23 hr 56 min and 4s (not 24 hr). True or False

4) The normal force on the above coin depends on its mass, but the maximum speed v_max is mass independent. True or False

A musician in a concert hall is tuning her wind instrument. When she plays a short note she hears the echo of the note return from the opposite side of the 50.0 meter long auditorium 0.294 seconds later. Model the instrument as a tube closed at one end, if the instrument is properly tuned the note of the musician played would have a frequency of 233.082 Hz, but instead has a frequency of 226.513 Hz. This note is the first overtone, since the fundamental frequency is suppressed on this instrument. 1) What is the speed of sound in the concert hall on that day? 2) What is the temperature of the concert hall on that day in Kelvin? 3) What is the length of the tubing on the musician's instrument in meters? 4) How much does the musician need to change the length of the tubing to be in tune on that day? Does the tube need to be shortened or lengthened? Find the change in length of the tube, and make sure to use a negative number if the tube needs to be shorter. ( answer in meters.) 5) What is the fundamental frequency of this instrument when correctly tuned? 6) What is the second overtone of the correctly tuned instrument?  

A musician in a concert hall is tuning her wind instrument. When she plays a short note she hears the echo of the note return from the opposite side of the 50.0 meter long auditorium 0.294 seconds later. Model the instrument as a tube closed at one end, if the instrument is properly tuned the note of the musician played would have a frequency of 233.082 Hz, but instead has a frequency of 226.513 Hz. This note is the first overtone, since the fundamental frequency is suppressed on this instrument. 1) What is the speed of sound in the concert hall on that day? 2) What is the temperature of the concert hall on that day in Kelvin? 3) What is the length of the tubing on the musician's instrument in meters? 4) How much does the musician need to change the length of the tubing to be in tune on that day? Does the tube need to be shortened or lengthened? Find the change in length of the tube, and make sure to use a negative number if the tube needs to be shorter. ( answer in meters.) 5) What is the fundamental frequency of this instrument when correctly tuned? 6) What is the second overtone of the correctly tuned instrument?  

if fusion power were harnesed today, the abundant energy that results would probably sustain and even further encourage our present appetite for continued growth and in a relatively few doubling times produce an appreciable fraction of solar power input to earth. make an argument that the current delay in harnessing fusion is a blessing for the human race

1. A wheel that initially spins at 2 revolutions/sec is braked uniformly to a stop in ½ second. How many revolutions does the wheel make while coming to a stop?

2. If a person has a speed of 3 m/s and is located 2-m from the axis of rotation of a merry-go-round, what is the person's angular velocity?

3. A hockey player with a mass of 46.0 kg is traveling due east with a speed of 2.95 m/s. A second hockey player with a mass of 66.0 kg is moving due south with a speed of 6.95 m/s. They collide and hold on to each other after the collision. Find the direction they travel after the collision given as an angle measured south of east.

4. The Seattle ferris wheel has a radius of 11-m and travels with an angular velocity of 1.5 rad/sec. What is the normal force (apparent weight) acting on a 57-kg person at the bottom of the swing?

5. A 65 kg snowboarder travels down a 37° incline at 6.2 m/s. In order to stop before hitting a tree, the snowboarder quickly turns their board to increase the coefficient of kinetic friction to 1.9. What is the normal force between the snowboarder and the ground?

6. A 65 kg snowboarder travels down a 37° incline at 6.2 m/s. In order to stop before hitting a tree, the snowboarder quickly turns their board to increase the coefficient of kinetic friction to 1.9. What is the friction force between the snowboarder and the ground?

7. A 65 kg snowboarder travels down a 37° incline at 6.2 m/s. In order to stop before hitting a tree, the snowboarder quickly turns their board to increase the coefficient of kinetic friction to 1.9. How far does the snowboarder slide before stopping? Assume the path the snowboarder takes is straight down the slope.

1) A food server is holding a 2 kg food tray as shown. Estimate the torque with respect to an axis through his shoulder exerted by the force of the tray on his hand. Explain.

[Note that I am not asking you for the net torque, just the torque from one force (the tray pushing on his hand).]

2)You can probably stand flatfooted on the floor and then rise up and balance on your tiptoes. Why are you unable to do this if you stand so your toes are touching a wall? (Try it!) Use physics from this chapter to explain.

3)When a ladder leans against a wall (and stays put) there are at least 4 forces on the ladder.

a) Describe them, including the object causing the force and the object the force acts on.

b) If you lean the ladder down too low it will slide and fall. Describe why this occurs in good physics terms

Suppose you take and hold a deep breath on a chilly day, inhaling 2.5 L of air at 0 ∘C and 1 atm.

1.

How much heat must your body supply to warm the air to your internal body temperature of 37 ∘C?

Express your answer to three significant figures and include the appropriate units.

2.

By how much does the air's volume increase as it warms?

Express your answer using two decimal places and include the appropriate units.

A ball is thrown upward with initial velocity v0 = 15.0 m/s at an angle of 30° with the horizontal. The thrower stands near the top of a Jong hill which slopes downward at an angle of 20°. Determine how far down the slope the ball strikes.

2) Operating a steady-state, a well insulated mixing chamber receives two input liquid streams of the same substance but with temperatures T1 and T2 and mass flow rates m ̇ 1 and m ̇ 2 respectively. The streams are mixed in the chamber, exiting as a single stream with T3 and m ̇ 3. Assuming the substance is incompressible with constant specific heat C, that potential energy, kinetic energy, and pressure changes are negligible, obtain an expression for

a) T3 in terms of T1, T2 and the ratio of the mass flow rates m ̇ 1/m ̇ 3.

b) the rate of entropy production per unit mass exiting the chamber in terms of C, T1/T2 and m ̇ 1/m ̇ 3.

c) For fixed values of C and T1/T2, determine the value for m ̇ 1/m ̇ 3 for which the rate of entropy production per unit mass out, σ ̇/m ̇3, is a maximum. (Hint start with an expression for σ ̇/m ̇3 as a function of m ̇ 1/m ̇ 3.)

NOTE: m * = M (Dot)

A 2290 kg car traveling at 11.7 m/s collides with a 2620 kg car that is initially at rest at the stoplight. The cars stick together and move 3.30 m before friction causes them to stop. Determine the coefficient of kinetic friction betwen the cars and the road, assuming that the negative acceleration is constant and that all wheels on both cars lock at the time of impact.

When you shine a laser with unknown wavelength through a diffraction grating with 1000 slits/mm, you observe the m = 1 bright fringe on the screen with an angle of 26 degrees away from the center of the grating.

What is the wavelength of your laser?

Plug in the relevant numbers to solve for your laser pointer photon wavelength in nanometers.

If the new diffraction bright fringe is at a LARGER angle than the diffraction bright fringe from the first grating, is the new diffraction spacing larger or smaller than the old diffraction line spacing?

Similarly, what if the new diffraction bright fringe is at a SMALLER angle?