Two small loudspeakers emit sound waves of different frequencies equally in all directions. Speaker A has an output of 1.30 mW, and speaker B has an output of 1.90 mW. Two speakers A and B are represented as points which serve as the centers of concentric circles representing sound waves emanating from the speakers. The concentric circles about speaker A are spaced more closely together than the concentric circles about speaker B. The points lie along a horizontal line, and speaker A is 5.00 m to the left of speaker B. A vertical line is drawn that intersects the horizontal line at a distance of 3.00 m from the left speaker and 2.00 m from the right speaker. Point C lies along this vertical line at a distance of 4.00 m above the point of intersection. (a) Determine the sound level (in decibels) at point C in the figure if only speaker A emits sound. (Enter your answer to at least one decimal place.) dB (b) Determine the sound level (in decibels) at point C in the figure if only speaker B emits sound. (Enter your answer to at least one decimal place.) dB (c) Determine the sound level (in decibels) at point C in the figure if both speakers emit sound. (Enter your answer to at least the nearest dB.) dB/Users/crystaldawnmcclendon/Desktop/14-p-064.gif

Suppose a solid cylinder of radius R is caused to rotate with a torque of known magnitude about an axis through its center. The same torque is then applied to a hollow cylinder of outer radius R and inner radius r. If their masses are equal, which object has the greater angular acceleration?

A. The solid cylinder has greater angular acceleration.

B. Both cylinders have the same acceleration

C. The hollow cylinder has a grater angular acceleration

A 20 mW 360 nm laser is incident on a metal anode. The metal in the anode has a work
function of 1.80 eV.
a) What voltage must be applied to completely stop the photo-electrons?
b) In the absence of an applied voltage, what current would be measured? assuming
i) all photons in the laser produce a photo-electron and
ii) all photo-electrons reach the cathode
c) Why are these unrealistic assumptions?
d) What is the deBroglie wavelength of the emitted electrons?

Give two examples explaining where using conservation of energy to solve a problem is easier than other the methods. Explain how you would use energy to solve the problem and why it is easier. 75-150

Explain in your own word the concepts of viscous damping, coulomb damping and stiffness force in a vibration system.

1. A 0.4 kg ball hits the ground (vertically) at a speed of 6 m/s, bouncing back in the opposite direction at 4 m/s. Calculate the magnitude of the impulse provided by the ground to the ball.

A. 2 Ns

B. 10 Ns

C. 4 Ns

D. 0.8 Ns

2.Calculate the recoil speed of a 1.4 kg rifle shooting 0.006 kg bullets with muzzle speed of 800 m/s

A. 3.43 m/s

B. 571 m/s

C. 1.22 m/s

D. 6.42 m/s

3. A 20 kg cart moving at 10 m/s bumps from behind an 80 kg cart initially moving at 2 m/s in the same direction. The two carts stick to each other after the collision. Calculate the speed of the carts after they collide.

A. 8.4 m/s

B. 3.6 m/s

C. 7.6 m/s

D. 0.4 m/s

4. A 40 kg cart moving from South toward North at 6 m/s has a totally inelastic collision with a 20 kg cart moving at 3 m/s in the opposite direction. What is the speed and the direction of motion of the two carts just after the collision?

A. 3 m/s toward North

B.5 m/s toward South

C.5 m/s toward North

D.3 m/s toward South

A person with mass m₁ = 68 kg stands at the left end of a uniform beam with mass m₂ = 109 kg and a length L = 2.5 m. Another person with mass m₃ = 50 kg stands on the far right end of the beam and holds a medicine ball with mass m₄ = 8 kg (assume that the medicine ball is at the far right end of the beam as well). Let the origin of our coordinate system be the left end of the original position of the beam as shown in the drawing. Assume there is no friction between the beam and floor.

1. What is the location of the center of mass of the system?

2. The medicine ball is throw to the left end of the beam (and caught). What is the location of the center of mass now?

3. What is the new x-position of the person at the left end of the beam? (How far did the beam move when the ball was throw from person to person?)

4. To return the medicine ball to the other person, both people walk to the center of the beam. At what x-position do they end up?

Present the advantage of Forward-Looking Infrared (FLIR) systems.

1)how could you use Pascal's principle to lift a heavy mass with the least effort ?
2) how would you calculate the volume of liquid the cube displaces?
3) how does the density of the liquid effect the upward force(buoyant force) acting on the cube ?

A proton enters a vertical magnetic girlf of magnitude 0.0500 T and travels east. what is the direction of the magnetic force on the proton?

A parallel plate capacitor has an area of A=200 cm^-2    and 0.50 cm plate distance. The capacitor is firstly connected to a power supply that has potential difference V0=30V    and after charged the power supply is disconnected. After then a sheet of insulating plastic material is inserted between the plates (completely filling the space between them). With the plastic material the potential difference decreases to 10 V while the charge on capacitor remains the constant. Find ;
a) the original (while filled air) capacitance C0 .

b) the stored charge Q

c) the capacitance C after the dielectric is inserted.

d) the dielectric constant of the dielectric.

e) the original electric field E0 between the plates.

f) The stored energy at the original capacitor.

A capacitor is connected to a battery and placed in a magnetic field (-z direction) to form a velocity selector. A charge moving at 3,479.6 m/s is not deflected by the velocity selector. If the voltage of the battery is 7 volts and the distance between the sheets is 0.3 meters, what is the amount of the magnetic field in milli-Tesla?

The vector position of a 3.90 g particle moving in the xy plane varies in time according to r with arrow1 = 3i + 3j t + 2jt2 where t is in seconds and r with arrow is in centimeters. At the same time, the vector position of a 5.60 g particle varies as r with arrow2 = 3i − 2it2 − 6jt.

A person with mass mp = 78 kg stands on a spinning platform disk with a radius of R = 2.37 m and mass md = 198 kg. The disk is initially spinning at ω = 1.4 rad/s. The person then walks 2/3 of the way toward the center of the disk (ending 0.79 m from the center).

1)What is the total moment of inertia of the system about the center of the disk when the person stands on the rim of the disk?

2)What is the total moment of inertia of the system about the center of the disk when the person stands at the final location 2/3 of the way toward the center of the disk?

3)What is the final angular velocity of the disk?

4)What is the change in the total kinetic energy of the person and disk? (A positive value means the energy increased.)

5)What is the centripetal acceleration of the person when she is at R/3?

6)If the person now walks back to the rim of the disk, what is the final angular speed of the disk?

Consider two photons, one with energy 1 = 2 MeV traveling to the right, and the other with energy 2 = 3 MeV moving to the left. The two photons collide head-on and produce a positron-electron pair. In this problem you will calculate the velocities of the two particles after the collision. Use the Doppler Shift equation to find the velocity of a frame of reference S' such that the two photons have the same energy. Which direct is S