#4. A vase was placed on the coffee table. The coefficient of static friction between the vase and the table is 0.3689, whereas the coefficient of kinetic friction is 0.1339. The vase weighs 1.0707kg. A cat decided to redecorate the room by pushing the vase off the table. As the cat pushes the vase with its paw, the vase moves. Then, the cat maintains a constant applied force of 7.37N on the vase in the positive x-direction. What is the acceleration of the vase in the x-direction during the time when the vase is moving?

#6. A student has two springs. Spring 1 is twice the
mass of spring 2. The student first puts spring 1 into a massless
pouch and suspends it from spring 2. Spring extension was noted to
be 12.69cm. Then, they put spring 2 into a massless pouch and
suspend it from spring 1. Spring extension was noted to be
16.42cm.

What is the ratio of k1/k2?

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A hockey puck (1) of mass 130 g is shot west at a speed of 8.40 m/s. It strikes a second puck (2), initially at rest, of mass 124 g. As a result of the collision, the first puck (1) is deflected at an angle of 32° north of west and the second puck (2) moves at an angle of 40° south of west. What is the magnitude of the velocity of puck (1) after the collision?

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a) If an atom has an electron in the **n=3** state
with **m=1**, what are the possible values of l, the
angular momentum quantum number?

b)What are the possible values of **m** for an
electron in the **n=3** state?

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Does a flat mirror produce a real or virtual image? What is its magnification?

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A block of mass m1=4.00 kg moves on the surface of a horizontal table. The coefficient of kinetic friction between the table top and m1 is equal to 0.350. Block 2 of mass m2=2.00 kg is tied to m1 via a string that passes over a frictionless, massless pulley. The two blocks start from rest and m2drops by a distance L=1.75 m to the floor.

Calculate the net work Wnet done by all the forces acting on the system

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Many people think that quantum physics is used only in the
laboratory. In fact, many devices that depend on quantum physics
for their operation are used in business, industry, and our
everyday lives. Give examples of four such uses, and for each one,
describe how quantum physics is essential for its operation. Try to
pick four devices that appear, to the non-physics student, to be as
different from each other as possible.

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An object that weighs 1180 N rests on a lever at a point 0.370 m from a support. On the same side of the support, at a distance of 3.00 m from it, an upward force with magnitude F is applied. Ignore the weight of the board itself. If the system is in equilibrium, what is F? Express your answer in Newtons. where P = 1180 and x = 0.370. N

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what are the classical explanation and quantum explanation for the existence of the fringe pattern?

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A) Three equal charges 6.3 ?C are located in the xy-plane, one at (0 m, 51 m), another at (56m,0m),and the third at(57m,?66m).

Find the magnitude of the electric field at the origin due to these three charges. The value of the Coulomb constant is 8.98755

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A block with mass mA = 15.0 kg on a smooth horizontal surface is connected by a thin cord that passes over a pulley to a second block with mass mB = 6.0 kg which hangs vertically.

Determine the magnitude of the acceleration of the system.

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

If initially mA is at rest 1.250 m from the edge of the table, how long does it take to reach the edge of the table if the system is allowed to move freely?

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

If mB = 1.0 kg, how large must mA be if the acceleration of the system is to be kept at g100?

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

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Two small forward-facing speakers are 2.50 m apart. They are both emitting, in phase with each other, a sound of frequency 1100 Hz in a room where the speed of sound is 344 m/s. A woman is standing opposite the midpoint between the speakers and is initially 35.0 m from the midpoint. As she slowly walks parallel to the line connecting the speakers, at what angle θ (relative to the centerline coming outward from the midpoint between the speakers) will she first hear no sound?

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Q2) A 400-gram package lying on a horizontal surface is attached to a horizontal string which passes over a smooth pulley. When a mass of 200 grams is attached to the other end of the string, the package is on the point of moving. Find μS, the coefficient of static friction

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**Where there are multiple forces acting on the same
object, draw a free-body diagram (i.e a diagram where each vector
for each of the different forces is shown):** A book on a
table has a coefficient of static friction of 0.1 and a coefficient
of kinetic friction of 0.05. The book has a mass of 1kg. The table
has a length of 3m. Suppose you gently tilt the table until the
book starts to slip and then leave the angle of the book at that
critical angle afterwards. How long will it take the book to slide
to the end of the table?

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Question C A spacecraft for extrasolar travel uses a sail to reflect light back toward the sun. At earth’s orbit the sunlight has an intensity of 1368 W/m2. The spacecraft has a mass of 2000 kg. a) [8] Determine the required sail to achieve an initial acceleration of the 9.8m/s2 b) [2] if it were black rather than reflective what would the initial acceleration be? Question D [8] Show that the units on the right side of eq 22-27 are those expected for c |

how to do question D）

（Only help me to do question D）thanks）

Question A [4 x 4 marks] Early morning sunlight passes through
polarizing sunglasses and hits a person’s eye lid (so they are not
blinded by this light)

What orientation is the electric field at the persons
eye?

The Poynting vector for this light is 650W/m2 West.

Find the electric field amplitude

Find the magnetic field amplitude.

Question B [ 4 x 4 marks] A photon with an energy of 10.2eV is
absorbed by a hydrogen atom traveling in the opposite direction
with a speed of 1000 m/s.

What is the energy in Joules of the photon?

What is the wavelength, frequency and speed of the
photon

What is the momentum of the photon?

What is the speed of the atom after the photon is
absorbed?

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An electron and a positron are located 17 m away from each other and held fixed by some mechanism. The positron has the same mass and the same magnitude of charge as those of the electron, but its charge is positive. The electron and the positron are released at the same time by the mechanism. The electron and the positron begin to speed up towards each other. What velocities should they have when they are 1.3 m away from each other?

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