A 12.0-kg package in a mail-sorting room slides 2.00 m down a chute that is inclined at 53.0∘53.0∘ below the horizontal. The coefficient of kinetic friction between the package and the chute’s surface is 0.40.

I know hot to calculate Work for each separate force on the package. But how would you use the Work Kinetic Energy Theorem to find the package's change in kinetic energy?

Thanks!

Below is a diffraction problem. I have the solutions to the problem but I don't know how to arrive at these solutions.

A) In an experiment two slits are separated by 0.22mm and illuminated by light of wavelength 640nm. How far must a screen be placed in order for the bright fringes to be separated by 5 mm? (1.72 m)

B) A soap film is illuminated by white light normal to its surface. The index of refraction of the film is 1.50. Light corresponding to a wavelength in air of 600 nm is intensified in the reflected beam. The smalled thickness of the film is.. (0.10 micrometers)

C) Unpolarized light of intensity Io passes through a pair of polarizing filters with their axes making an angle of 38 degrees. What fraction of Io passes through? (0.31)

Let be a cylindrical box with a volume of 1200cm^3 and a weight of 0.13kg. 

-What is the maximum mass of lead that we can put in the box without it being submerged in water? 
 
The density of lead is 11.4 t/m3.

Can you comment how is it incomplete, What is missing?

A purple beam is hinged to a wall to hold up a blue sign. The beam has a mass of mb = 6.7 kg and the sign has a mass of ms = 17.4 kg. The length of the beam is L = 2.83 m. The sign is attached at the very end of the beam, but the horizontal wire holding up the beam is attached 2/3 of the way to the end of the beam. The angle the wire makes with the beam is θ = 34.5°.

1)What is the tension in the wire?

2)What is the net force the hinge exerts on the beam?

3)The maximum tension the wire can have without breaking is T = 946 N. What is the maximum mass sign that can be hung from the beam?

Two charges are placed on the x axis. One of the charges (q1 = +7.73C) is at x1 = +3.00 cm and the other (q2 = -23.7C) is at x2 = +9.00 cm. Find the net electric field (magnitude and direction given as a plus or minus sign) at (a) x = 0 cm and (b) x = +6.00 cm.

An electric ceiling fan is rotating about a fixed axis with an initial angular velocity magnitude of 0.200 rev/s . The magnitude of the angular acceleration is 0.883 rev/s2 . Both the the angular velocity and angular accleration are directed counterclockwise. The electric ceiling fan blades form a circle of diameter 0.760 m .

Two particles are fixed on an x axis. Particle 1 of charge 51.4 μC is located at x = -22.8 cm; particle 2 of charge Q is located at x = 10.8 cm. Particle 3 of charge magnitude 20.8 μC is released from rest on the y axis at y = 22.8 cm. What is the value of Q if the initial acceleration of particle 3 is in the positive direction of (a) the x axis and (b) the y axis?

Please let me know about the material structure and properties of Solar energy devices.

Two stationary positive point charges, charge 1 of magnitude 3.45nC and charge 2 of magnitude 1.80nC , are separated by a distance of 40.0cm . 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

5. Prove the Snell’s Law using:
   1. The fact that an homogeneous surface does not change the transversal momentum of the wave (Photon).
   2. Maxwell’s equations.
   3. The variational principle or Fermat’s principle.

Point charges of 9.00 nC are situated at each of three corners of a square whose side is 0.450 m .

a. What is the magnitude of the resultant force on a point charge of -4.00 μC if it is placed at the center of the square?

b. What is the magnitude of the resultant force on a point charge of -4.00 μC if it is placed at the vacant corner of the square?

Discuss the basic aspects of Tight-binding approximation (what is it, how and when this model is applicable, it's motivation, why is it important, it's limitations)? What are the differences and similarities of tight-binding model and free-electron model?

The speed of a projectile when it reaches its maximum height is 0.56 times its speed when it is at half its maximum height. What is the initial projection angle of the projectile?

A communications satellite is in a synchronous orbit that is 3.47