1. A potter's wheel is rotating around a vertical axis through its center at a frequency of 1.8rev/s . The wheel can be considered a uniform disk of mass 5.0kg and diameter 0.30m . The potter then throws a 3.2-kg chunk of clay, approximately shaped as a flat disk of radius 8.0cm , onto the center of the rotating wheel.

What is the frequency of the wheel after the clay sticks to it? Ignore friction.

Express your answer using two significant figures.

f =		rev/s

As discussed in the previous question, the second stage of the propulsion system is used to boost the spacecraft from Martian orbit into an interplanetary trajectory and return to Earth.

Knowing that the thrust generated by the second stage is 2620 N and the rocket exhaust velocity is 430 m/s; calculate the minimum amount of propellant needed to have a chance of returning to Earth. Assume that the thruster must be turned on for 2 minutes in order to reach the proper velocity.

Give your answer in kg.

Thank you for your time!

Explain what you understand from 'Ohm's law'. In about 50 words, explain practical consequences of Ohm's law, with examples from real life, as needed.

Problem 14.71 IP Standing Waves in the Human Ear The human ear canal is much like an organ pipe that is closed at one end (at the tympanic membrane or eardrum) and open at the other (Figure 1) . A typical ear canal has a length of about 2.4 cm.

Part A What are the fundamental frequency and wavelength of the ear canal? Express your answer using two significant figures. f1 =_______ Hz

Part B Express your answer using two significant figures. λ1 = _____cm

Part C Find the frequency and wavelength of the ear canal's third harmonic. (Recall that the third harmonic in this case is the standing wave with the second-lowest frequency.) Express your answer using two significant figures. f3 =_______ Hz

Part D Express your answer using two significant figures. λ3 =_____ cm

Part E Suppose a person has an ear canal that is shorter than 2.4 cm. Is the fundamental frequency of that person's ear canal greater than, less than, or the same as the value found in part A? Explain.

As an electron moves in the direction of the electric field lines...

Answer: It is moving from high potential to low potential and gaining electric potential energy.

Can someone explain why the electron is gaining electric potential energy if it is moving from high to low potential energy?

A 195-kg rugby player running east with a speed of 4.00 m/s tackles a 95.0-kg opponent running north with a speed of 4.5 m/s. Assume the tackle is a perfectly inelastic collision. (Assume that the +x-axis points towards the east and the +y-axis points towards the north.)

(a) What is the velocity of the players immediately after the tackle?

magnitude	_____ m/s
direction	________ ° counterclockwise from the +x-axis

(b) What is the amount of mechanical energy lost during the collision?
______J

A 100.0 m rod with a diameter of 3.0mm has a charge of 1004.0C. What is the approximate electric field 2.0mm from the surface of the rod, not near either end?

A) 9.0*10¹¹ r N/C

B) - 9.0*10¹¹ r N/C

C) - 5.2*10¹³ r N/C

D) 5.2*10¹³ r N/C

The answer is D, I am not sure how they got that answer, can you please explain and show your work. Thanks in advance

You are exploring a distant planet. When your spaceship is in a circular orbit at a distance of 630 km above the planet's surface, the ship's orbital speed is 5500 m/s . By observing the planet, you determine its radius to be 4.48×10^6 m. You then land on the surface and, at a place where the ground is level, launch a small projectile with initial speed 13.6 m/s at an angle of 30.8∘ above the horizontal. If resistance due to the planet's atmosphere is negligible, what is the horizontal range of the projectile? Please explain process

What is the current thinking on the little hierarchy problem in light of a potential Higgs mass above 120 GeV? A few years ago, at least, I remember various phenomenologists saying that this at least makes life rather difficult for the MSSM.

Goldstein's Classical Mechanics has a puzzling few sentences in his discussion of orbits.

Referring to the case of orbit where the energy is low enough for the orbit to be bounded, he says :"This does not necessarily mean that the orbits are closed. All that can be said is that they are bounded, contained between two circles of radii r1 and r2 with turning points always lying on the circles."

Doesn't "bounded" automatically mean "closed"? The object cannot escape from the attractive force and hence returns over and over. At least, that is my understanding of the terms. Wikipedia says "The orbit can be open (so the object never returns) or closed (returning), depending on the total energy (kinetic + potential energy) of the system." But it also says "Orbiting bodies in closed orbits repeat their paths after a constant period of time." So the only way out I see is if a closed orbit is a special case of non-precessing bounded orbit.

A simple generator has a square armature 7.0cm on a side. The armature has 95 turns of 0.59-mm-diameter copper wire and rotates in a 0.800-T magnetic field. The generator is used to power a lightbulb rated at 12.0 V and 25.0 W. At what rate should the generator rotate to provide 12.0 V to the bulb? Consider the resistance of the wire on the armature.

Consider the work-energy theorem relating work done on an object and its change in kinetic energy. What is the formula? Explain in your own words what this formula gives you. Create an example. Include a graphical or picture representation that illustrates what all the variables are. Then exemplify the use of the formula with a simple problem of your own creation. The problem should be stated in words first. Every variable should have a well defined value with appropriate units. Finally, solve your problem.
( please show image and explain clearly)

A person walks into a room and switches on the ceiling fan. The fan accelerates with constant angular acceleration for 18s until it reaches its operating angular speed of 2.0rotations/s - after that its speed remains constant as long as the switch is "on". The person stays in the room for a short time; then, 5.5 minutes after turning the fan on, she switches it off again and leaves the room. The fan now decelerates with constant angular acceleration, taking 2.4 minutes to come to rest.

What is the total number of revolutions made by the fan, from the time it was turned on until the time it stopped?

Express your answer using two significant figures.

Two isotopes of carbon, carbon-12 and carbon-13, have masses of 1.993 10-26 kg and 2.159 10-26 kg, respectively. These two isotopes are singly ionized (+e) and each is given a speed of 7.88 105 m/s. The ions then enter the bending region of a mass spectrometer where the magnetic field is 0.8400 T.

Determine the spatial separation between the two isotopes after they have traveled through a half-circle.