An empty tin can with height of 30cm and a diameter of 15cm is open at one end and closed at the other end. If the vertical can, with open end down, be slowly immersed in water, how far the water will rise inside the can when the closed end is 10 cm below the water surface?

I know this is easy, but when I'm solving for h, I'm getting a negative value, means that the can will be filled completely?

A sample has a activity of 0.0089 Bq per gram of carbon. (a) Find the age of the sample, assuming that the activity per gram of carbon in a living organism has been constant at a value of 0.23 Bq. (b) Evidence suggests that the value of 0.23 Bq might have been as much as 44% larger. Repeat part (a), taking into account this 44% increase.

The emissivity of the human skin is 97.0 percent. Use 35.0 °C for the skin temperature and approximate the human body by a rectangular block with a height of 1.64 m, a width of 35.5 cm and a length of 25.0 cm.
Calculate the power emitted by the human body.

What is the wavelength of the peak in the spectral distribution for this temperature?

Fortunately our environment radiates too. The human body absorbs this radiation with an absorbance of 97.0 percent, so we don't lose our internal energy so quickly. How much power do we absorb when we are in a room where the temperature is 21.0 °C?

How much energy does our body lose in one second?

Problem 6.21

A 5000kg truck is parked on a 12? slope.

Part A

How big is the friction force on the truck? The coefficient of static friction between the tires and the road is 0.90.

2. An ideal gas undergoes an isothermal expansion from one state to another.  In this process determine the following (using the sign conventions on page 413):
   • Q = 0, Q > 0 or Q < 0
   • W = 0, W > 0 or W < 0
   • ΔU = 0, ΔU > 0 or ΔU < 0

3. An ideal gas undergoes an isothermal process.  Which of the following are true (may be more than one):  a) No heat is added or removed from the gas, b) the internal energy of the gas does not change and/or c) the average kinetic energy of the molecules does not change.

4. An ideal gas undergoes an adiabatic expansion in which no heat flows into or out of the gas.  As a result determine which of the following properties of the gas increases (may be more than one): a) temperature, b) pressure and/or c) volume.  

5. Can you cool your kitchen by leaving your refrigerator door open?  Why or why not?

6. If 1500 J of heat is added to a system and the system does 1100 J of work, then what was the change in the internal energy of the system?   Assume the system is closed (i.e. a gas inside of a cylinder fitted with a movable piston).
7. ​​​​​​​

A 108 m long train starts from rest (at t = 0) and accelerates uniformly. At the same time (at t = 0), a car moving with constant speed in the same direction reaches the back end of the train. At t = 12 s the car reaches the front of the train. However, the train continues to speed up and pulls ahead of the car. At t = 32 s, the car is left behind the train. Determine, the car’s speed the train’s acceleration

42. You are working as an assistant to an air-traffic controller at the local airport, from which small airplanes take off and land. Your job is to make sure that airplanes are not closer to each other than a minimum safe separation distance of 2.00 km. You observe two small aircraft on your radar screen, out over the ocean surface. The first is at altitude 800 m above the surface, horizontal distance 19.2 km, and 25.08 south of west. The second aircraft is at altitude 1 100 m, horizontal distance 17.6 km, and 20.08 south of west. Your supervisor is concerned that the two aircraft are too close together and asks for a separation distance for the two airplanes. (Place the x axis west, the y axis south, and the z axis vertical.)

1. What is the momentum of a photon of light that has a frequency of 2.9 x 10^14 Hz?

a) 1.5 x 10^-28 kg m/s

b) 2.1 x 10^-28 kg m/s

c) 4.4 x 10^-28 kg m/s

d) 6.3 x 10^-28 kg m/s

e) 6.2 x 10^-28 kg m/s

ANSWER E

2. What is the momentum of a photon of light that has a wavelength of 480nm?

a) 1.1 x 10^-27 kg m/s

b) 2.2 x 10^-27 kg m/s

c) 1.8 x 10^-27 kg m/s

d) 1.4 x 10^-27 kg m/s

e) 2.0 x 10^-27 kg m/s

ANSWER: D

a. A hydrogen atom in the n=5 state decays to the n=3 state. What is the wavelength of the photon that the hydrogen atom emits? Use hc=1240 nm eV.

nm

b. While in the first excited state, a hydrogen atom is illuminated by various wavelengths of light. What happens to the hydrogen atom when illuminated by each wavelength?

486.3 nm?

491.3 nm?

335.1 nm?

For each wavelength pick from the following choices:

"stays in n=2 state" , "jumps to n=3 state", "jumps to n=4 state", "jumps to n=5 state", "jumps to n=6 state", "is ionized"

Note: For a transition between bound states (finite n) you need to match the correct wavelength to about 8 significant figures. For this problem, treat a transition as happening if the wavelength is within 1.0 nm.

Phasors
w=5+2i, u=2-2i, are two complex numbers written in component form.
a. Draw them in the imaginary plane.
b. find w and u in terms of their magnitude and phase.
c. Find the new imaginary number g=w*u, and demonstrate that the magnitude and phase of g is the same whether you multiply w*u in component form or simply multiply their magnitudes and phases together.