A converging lens with a focal length of 4.0cm is to the left of a second identical lens. When a feather is placed 11cm to the left of the first lens, the final image is the same size and orientation as the feather itself.

What is the separation between the lenses?

Express your answer using two significant figures.

How can we keep a penny standing on its edge in a stable manner? Explain

Does it depend on balancing to find it's center of mass....

A block of wood of mass 10.8 kg and density 4.42 x 102 kg/m3, floats on water. (a) What is the minimum amount of aluminum (density 2.70 x 103 kg/m3) that can be placed on top of the wood block and cause the block of wood and the aluminum to sink? (b) If instead it was a block of ice of mass 10.8 kg and density 8.90 x 102 kg/m3. What is the minimum amount of aluminum that can be placed on top of the ice block and cause the block of ice and the aluminum to sink? This question has been posted several times but they all have a different answer with little feedback.

Light from a source is incident on a slit of diameter 0.84 nm on a screen which is at a distance of 1.8 m. The position of the first minimum is 1.35 nm. Calculate the wavelength of the light.

Meteorologists measure the pressure inside a category 5 hurricane to be 0.97 atm very close to the ground (sea level). What is the wind speed of the hurricane? You can assume that the density of air is 1.29 kg/m3 and the pressure outside the hurricane is 1 atm.

In other problems and examples in the textbook we found the effective spring stiffness corresponding to the interatomic force for aluminum and lead. Let's assume for the moment that, very roughly, other atoms have similar values.

(a) What is the (very) approximate frequency f for the oscillation ("vibration") of H₂, a hydrogen molecule containing two hydrogen atoms? Remember that frequency is defined as the number of complete cycles per second or "hertz": f = 1/T. There is no one correct answer, since we're just trying to calculate the frequency approximately. However, just because we're looking for an approximate result doesn't mean that all answers are correct! Calculations that are wildly in disagreement with what physics would predict for this situation will be counted wrong.
f =    ??? cycles/s (hertz)

(b) What is the (very) approximate frequency f for the vibration of O₂, an oxygen molecule containing two oxygen atoms?
f = ??????    cycles/s (hertz)

(c) What is the approximate vibration frequency f of D₂, a molecule both of whose atoms are deuterium atoms (that is, each nucleus has one proton and one neutron)?
f =    ????? cycles/s (hertz)

(d) Which of the following statements are true? (Select all that apply.)

The estimated frequency for O₂ is quite accurate because the mass of an oxygen atom is similar to the mass of an aluminum atom. The true vibration frequency for D₂ is lower than the true vibration frequency for H₂, because the mass is larger but the effective "spring" stiffness is nearly the same, since it is related to the electronic structure, which is nearly the same for D₂ and H₂. The estimated frequencies for D₂ and H₂ are both quite accurate, because these are simple molecules, and the effective spring stiffness is expected to be the same as we found inside a block of metal. Neither of the estimated frequencies for D₂ and H₂ is accurate, but the ratio of the D₂ frequency to the H₂ frequency is quite accurate, because the "spring" represents the interatomic force, which is nearly the same for atoms with similar chemical structure (number of electrons).

1. A child is drinking a liquid with a straw. Which of the following statements is true? Why?

a. Longer Straws work better because the pressure is larger deeper down.

b. The pressure inside the straw depends on the viscosity of the liquid.

c. The pressure in the straw is reduced and the liquid is pushed upward by atmospheric pressure on the surface of the liquid.

2. If you hold a light tissue in your hands and gently blow across its top, the tissue will rise slightly because of what? Why?

a. Blowing across the tissue removes all of the air, and then the air below the tissue pushes the tissue up.

b. Collisions of the moving air with the tissue cause it to rise.

c. The pressure of moving air is less than that of static air.

3. Even though your car weighs several thousand pounds, it can easily be raised above your head by a pneumatic lift at the service station by a small motor pumping fluid through a pipe. This is an illustration of? Why?

a. Pascal's Principle

b. Archimedes' Principle

c. Newton's 3rd Law

4. Two identical objects, one light colored and the other dark colored, are the same elevated temperature, 50?. You now place them in a dark, much cooler room. Which object will reach the room's temperature first? Why?

a. The dark colored object

b. Both reach room temperature at the same time

c. As strange as it seems, neither object will ever reach room temperature because energy conservation prevents loss of energy

5. The circulatory system, lake inversion, shore breezes, and heating systems are all examples of what type of heat transfer? Why?

a. Convection

b. Radiation

PLEASE ANSWER WHY ON ALL QUESTIONS!

Solve the homogeneous differential eqation (1) for the radio circuit. Show that these terms will dissipate quickly, leaving only the particular solution.

The equation is a second-order differential equation with L=1/30 henrys, R=100 ohms and C in farads can vary as needed to tune to various input frequencies omega

A mass of 5 kg is placed on a horizontal surface with a coefficient of kinetic friction of 0.4. A force is applied vertically downward to it and another force of 81 Newtons is applied at 14 degrees below the horizontal. As it moves 5 meters in the +x direction it loses 180 Joules of kinetic energy. What is the amount of the force which is applied downward in Newtons?

A circuit is consisted of an inductor L, a capacitor C, and a resistor R. It is driven by an AC voltage of the form ?0sin (??). At the steady state, find (a) the charge and current as a function of time (b) the maximum amplitude of the current and the corresponding resonance frequency (c) the average power at the current’s resonance frequency (c) the quality factor Q

26.

A toy cannon uses a spring to project a 5.34 g soft rubber ball. The spring is originally compressed by 5.08 cm and has a force constant of 8.09 N/m. When the cannon is fired, the ball moves 15.1 cm through the horizontal barrel of the cannon, and there is a constant frictional force of 0.0318 N between the barrel and the ball.

(a) With what speed does the projectile leave the barrel of the cannon?
m/s
(b) At what point does the ball have maximum speed?
cm (from its original position)
(c) What is this maximum speed?
m/s

In a Young's double-slit experiment, a set of parallel slits with a separation of 0.102 mm is illuminated by light having a wavelength of 600 nm and the interference pattern observed on a screen 4.50 m from the slits. (a) What is the difference in path lengths from the two slits to the location of a second order bright fringe on the screen?

A horizontally projected beam of protons travels at 55 km/s into the space between two horizontal, parallel plates. The plates are separated by 7.4 cm, and they are 12 cm long. There is a uniform electric field between the plates of unknown strength. The beam enters the region exactly midway (vertically) between the plates and exits the region 7.2 microns closer to the lower plate. If it were a beam of electrons instead, everything else being the same, at what height above the lower plate would the beam exit the region between the plates? The proton mass is 1.67 × 10^-27 kg, and electron mass is 9.11 × 10^-31 kg. (THE ANSWER IS 5 CM)

The function of a wave for a wave over a tense rope is

y(x,t)=(0.350m)sin (10πt -3πx + π/4)

Where "x" is in meters and "t" in seconds. determine

A) Amplitud of the wave

B) Long of the Wave

C) Number of the wave

D) The period

E) The frecuency

F) Angular frecuency

G) Velocity of the Wave