what is the magnetic susceptibility of a sample? how does it change with different magnetic behaviours in the solid?

The figure shows a conical pendulum, in which the bob (the small object at the lower end of the cord) moves in a horizontal circle at constant speed. (The cord sweeps out a cone as the bob rotates.) The bob has a mass of 0.024 kg, the string has length L = 1.2 m and negligible mass, and the bob follows a circular path of circumference 1.2 m. What are (a) the tension in the string and (b) the period of the motion?

To a rough approximation, the Earth can be treated as a greybody sphere with uniform temperature, absorptance ? = 0.70 and emissivity ? = 0.61. The low absorptance is largely due to reflection of the incoming sunlight by clouds and ice, while the low emissivity is largely due to greenhouse gases in the atmosphere.

a) Over timescales of decades, the total solar irradiance at the Earth varies between about 1360.3 W/m² and 1362.0 W/m² . Using the greybody Earth approximation, how large of a temperature change can be expected due to these natural changes in solar irradiance? [Answer in K as a positive number.]

b) Over the last century, the amount of CO2 in the atmosphere has increased dramatically, which has resulted in a change in ? from 0.62 to 0.61. Using the greybody Earth approximation, how large of a temperature change can be expected due to this change in emissivity? [Answer in K as a positive number.]

NOTE: The answers to a) and b) are NOT 0.1 K

Your manager wants you to design a new superinsulated hot-water heater for the residential market. A coil of Nichrome wire is to be used as the heating element. Calculate the length of wire required. (The water heater is cylindrical in shape, and is completely filled with water. Let the diameter of the water heater be 50 cm and its height 0.8 m. The coil of Nichrome wire is located inside the water heater, in contact with the water. Assume that the diameter of the Nichrome wire is 2.0 mm and that the water, initially at 20°C, is to be heated to 77°C in 1.0 h. Let the voltage used by the water heater be 120 V.)

1. Two students are kayaking on the Saint John River. Initially, they are floating directly beside each other chatting and moving with the river current at 1.50 m/s downstream. Student A pushes away from Student B and sees Student B floating away from them at 1.00 m/s in the upstream direction. The combined inertia of Student A and their kayak is 100 kg and the combined inertia of Student B and their kayak is 120 kg. Assume that there is no friction between the kayaks and the water. a. Relative to the river flow, determine the velocities of the two students once they start moving away from each other (after the push). (Define your system to justify any conservation relations you might use, provide appropriate diagrams to describe the interaction and explain your solution approach.) b. What are the velocities of the two students once they are moving away from each other as seen from the perspective of someone on the shore of the river? c. What source energy does Student A expend in pushing the two kayaks apart?

If the volume is the same in the whole process, the process is performed with an isochoric.

Select one:
True
False

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Every quasistatic process is necessarily reversible

Select one:
True
False

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The a / v2 term in the van der Waals equation is caused by the forces exchanging between molecules

Select one:
True
False

1. What is the physics behind the light amplification of optical amplifiers? What are the required conditions to make the amplification happen?

2. Describe what happens below, at, and above the lasing threshold of a laser in terms of its output power, population inversion, and gain coefficient.

If a person of mass MM simply moved forward with speed VV, his kinetic energy would be 12MV212MV2. However, in addition to possessing a forward motion, various parts of his body (such as the arms and legs) undergo rotation. Therefore, his total kinetic energy is the sum of the energy from his forward motion plus the rotational kinetic energy of his arms and legs. The purpose of this problem is to see how much this rotational motion contributes to the person's kinetic energy. Biomedical measurements show that the arms and hands together typically make up 14.0 %% of a person's mass, while the legs and feet together account for 38.0 %% . For a rough (but reasonable) calculation, we can model the arms and legs as thin uniform bars pivoting about the shoulder and hip, respectively. In a brisk walk, the arms and legs each move through an angle of about ±30∘±30∘ (a total of 60∘60∘) from the vertical in approximately 1 second. We shall assume that they are held straight, rather than being bent, which is not quite true. Let us consider a 70.0 kgkg person walking at 5.00 km/hkm/h having arms 70.0 cmcm long and legs 90.0 cmcm long.

1.What is the average angular velocity of his arms and legs?

2.Using the average angular velocity from part A, calculate the amount of rotational kinetic energy in this person's arms and legs as he walks.

3.What is the total kinetic energy due to both his forward motion and his rotation?

4.What percentage of his kinetic energy is due to the rotation of his legs and arms?

In a spring gun system, a spring with a spring force constant 420 N/mN/m  , is compressed 0.13 mm . When fired, 80.9 %% of the elastic potential energy stored in the spring is eventually converted into kinetic energy of a 6.10×10⁻² kgkg uniform ball that is rolling without slipping at the base of a ramp. The ball continues to roll without slipping up the ramp with 89.6 %% of the kinetic energy at the bottom converted into an increase in gravitational potential energy at the instant it stops.

a)What is the velocity of the ball's center of mass at the base of the ramp?

Express your answer using two significant figures.

b)At this position, what is the velocity of a point at the top of the ball?

Express your answer using two significant figures.

c)At this position, what is the speed of a point at the bottom of the ball?

Express your answer using two significant figures.

d)What maximum vertical height up the ramp does the ball move?

Take the free fall acceleration to be 9.80m/s29.80m/s2. Express your answer using two significant figures.

Mahmut with mass 70.0 kg and Güllü with mass 45.0 kg are skating. While Mahmut stands at rest, He is struck by Güllü. She is moving at 15.0 m/s before she collides with him. Güllü has a velocity of magnitude 10.00 m/s at an angle of 55.0 ∘ from her initial direction after the collision. Both skaters move on the frictionless and horizontal surface .

a)Find the magnitude of Mahmut's velocity after the collision?

b)Find the direction of Mahmut's velocity after the collision?

c)Find the change in total kinetic energy of the two skaters as a result of the collision?

a. Prediction

b. Result or consequence

c. Recommendation/ Call for action

(a) The Hubble Space Telescope is in a nearly circular orbit, approximately 610 km (380 mi) above the surface of the Earth. Estimate its orbital period from the generalized version of Kepler’s third law.

(b) Communications and weather satellites are often placed in geosynchronous orbits. A geosynchronous orbit is an orbit about the Earth with orbital period P exactly equal to one sidereal day. A special kind of geosynchronous orbit is when the satellite has an inclination of 0˝ from the Earth’s ecliptic plane and is at the equator. This is a geostationary orbit, also called a ‘parking orbit’ because it always appears ‘parked’ at a fixed location in the sky, above a fixed location on the earth. At what altitude must these satellites be located? What is the orbital velocity vgs of a satellite on a circular geostationary orbit?

(c) Is it possible for a satellite in a geosynchronous orbit to remain ‘parked’ over any location on the surface of the Earth? Why or why not?

A particle of rest energy 800 MeV decays in its rest frame into two identical particles of rest energy 250 MeV. What are the kinetic energies (in MeV), momenta (in MeV/c), and velocities (in units of c) of the daughter particles?

Refer to the previous problem. The parent particle moves in the lab with kinetic energy 800 MeV, and one daughter particle is emitted along the parent’s direction of motion. Find the lab kinetic energy (in MeV) for the daughter emitted backwards in the parent’s rest frame.

(I'm looking for help on the second problem.)