True/False please

1. The magnetic field is always conservative

2. Gauss'law for magnetism reflects the fact that there are no electric monopoles.

3. An electrically charged rod will attract a piece of magnetic material.

4. In an AC circuit, the complex power S represents the power supplied to the capacitors and inductors.

5. The capacitance of a parallel plate capacitor increases when a piece of dielectric material is inserted between the plates.

6. If an AC circuit has tow sources with different frequencies, we can add the solutions for each source in phasor space.

7. The ultimate source of all electromagnetic phenomena is electric charges in motion.

8. In an AC circuit, the average power supplied to a resistor is zero.

9. The magnetic field cannot ever do any work.

10. The instantaneous power supplied to any circuit element is always p(t) = i(t)v(t)

11. Both the voltage and current for an inductor must be continuous in time.

12. The relative permeability of a ferromagnetic substance is <1

Thank you!

How conservation laws are tested experimentally independently from each other? what do I mean by that question?

It seems that to test one conservation law experimentally, such as conservation of energy, we will have to assume other conservation laws are correct such as conservation of charge and conservation of momentum and angular momentum...etc.

But to really test any conservation law one has to check if one of them is valid independent from any other one. Is this possible experimentally? if not then how scientists check conservation laws?

The driver of a 1350 kg car, initially traveling at 10.1 m/s, applies the brakes, bringing the car to rest in a distance of 22.0 m.

(a) Find the net work done on the car.

(b) Find the magnitude and direction of the force that does this work. (Assume this force is constant.)

magnitude,direction

You have probably seen people jogging in extremely hot weather and wondered "Why?" As we shall see, there are good reasons not to do this! When jogging strenuously, an average runner of mass 68.0 kg and surface area 1.85 m2 produces energy at a rate of up to 1330 W , 80.0 % of which is converted to heat. The jogger radiates heat, but actually absorbs more from the hot air than he radiates away. At such high levels of activity, the skin's temperature can be elevated to around 33.0 ∘C instead of the usual 30.0 ∘C. (We shall neglect conduction, which would bring even more heat into his body.) The only way for the body to get rid of this extra heat is by evaporating water (sweating).

A: How much heat per second is produced just by the act of jogging? (J/s)

B: How much net heat per second does the runner gain just from radiation if the air temperature is 40.0 ∘C (104 ∘F)? (Remember that he radiates out, but the environment radiates back in.) (W)

C: What is the total amount of excess heat this runner's body must get rid of per second? (J/s)

D: How much water must the jogger's body evaporate every minute due to his activity? The heat of vaporization of water at body temperature is 2.42×10⁶ J/kg . (g)

E: How many 750 mL bottles of water must he drink after (or preferably before!) jogging for a half hour? Recall that a liter of water has a mass of 1.00 kg .

a) A car is driven along a curve at a speed of 38 m/s. If the car

What is a matter Entropy?

A stunt pilot in an air show performs a loop-the-loop in a vertical circle of radius 3.80* 10^3 m. During this performance the pilot whose weight is 644 N, maintains a constant speed of 2.05 *10^2 m/s.

(a) When the pilot is at the highest point of the loop determine his apparent weight in N.

(b) At what speed, in m/s, will the pilot experience weightlessness?

(c) When the pilot is at the lowest point of the loop determine his apparent weight in N. N

Please answer the questions fully and dont copy what was answered earlier on a previous post please

Lab 21 Part 1:

Materials- Slinky, Partner

Methods- A slinky was spread out 15 feet long with a partner and I sitting on the floor. Each of us was only holding a couple of coils while the rest was on the ground. Then each person sent over waves of different sizes and observed the different speeds that they passed by. Afterwards each person sent over transverse waves by moving the slinky side to side. Then we observed longitudinal waves by pushing the slinky in and pulling back.

            After that the partner sent a transverse wave and the same time as me. It was observed what happens when the waves pass each other. Then moving waves were made by moving one end of the slinky back and forth while the partners end was still to create standing waves.

1. What happened when the transverse waves reached your partner’s end? Did the reflected wave stay on the same side as the one you sent? Draw a diagram showing the incoming and reflected waves. 2. Did the waves go any faster or slower when you tried a variety of amplitudes? Explain how this agrees or disagrees with the equation for a transverse wave’s velocity. 3. What did you notice about the speed of the longitudinal waves compared to the transverse waves? 4. Explain what happened when you and your partner both sent waves on the same side. What kind of interference took place? 5. What happened when waves on opposite sides passed each other? 6. How did shortening the length of the spring affect the resonant frequencies? How does this confirm the relationship v = λ f when velocity is constant? (Hint: a shorter spring length means smaller wavelengths for each standing wave). 7. Using this knowledge, explain how musical instruments create higher and lower tones. Use a string instrument as an example.

An instrument used to measure the airspeed on many early low-speed airplanes was a venturi duct with a convergent-divergent duct (the front section's cross sectional area decreases in the flow direction, and the back section's cross sectional area increases in the flow direction. There is a "throat" in which the area is minimum.). Let A1 and A2 denote the inlet and throat areas, respectively. Let P1 and P2 denote the pressure at the inlet and throat, respectively. If the area ratio is A2/A1 = 1/4 and P1 - P2 = 80 lb/ft2. If the aircraft is flying at standard sea level, what is the velocity in knots?

Explain in less than 4 brief sentences how a Tesla coil works. Add a sketch.

An ancient wooden club is found that contains74g of carbon and has an activity of 7.7 decays per second.

Determine its age assuming that in living trees the ratio of 14C/12Catoms is about 1.3

A soccer player kicks a lock horizontally of a 46 m high cliff into a pool of water. If the player hears the sound of the splash 3.26 s later, (a)what was the initial speed given to the rock in m/s?assume a speed of sound in air is 343 m/s. (b)What if the temperature near the cliff suddenly falls to 0ﾟ C reducing the speed of sound of 331 m/s, what would the initial speed of the rock have to be in m/s for the soccer player to hear the sound of the splash 3.26 s after kicking the rock?

6. In each situation described below, compare the magnitudes of the two forces. Explain your answer in each case.

g. A truck attempts to tow a car. They are connected by a 2-m-long rope. At first the truck doesn’t pull hard enough, and the car doesn’t move. Compare the force exerted by the truck’s bumper on the rope to that exerted by the rope on the truck’s bumper. Also compare the force exerted by the rope on the car’s bumper to that exerted by the car’s bumper on the rope.

h. Finally the truck pulls hard enough so that the car begins to move. Compare the same pairs of forces as in (g) to each other.

i. An elevator is hanging from a strong cable. The elevator is at rest. Compare the force exerted by the cable on the elevator to that exerted by the elevator on the cable.

j. In (i) compare the tension in the cable to the weight of the elevator.

k. The elevator in (i) begins accelerating upward. Now compare the force exerted by the cable on the elevator to that exerted by the elevator on the cable.

l. In (k) compare the tension in the cable to the weight of the elevator.

m. The elevator in (i) is moving upward at a constant velocity. Now compare the force exerted by the cable on the elevator to that exerted by the elevator on the cable.

n. In (m) compare then tension in the cable to the weight of the elevator.

The potential difference from the cathode (negative electrode) to the screen of an old television set is +22,000 V. An electron leaves the cathode with an initial speed of zero.

a)Determine the kinetic energy of the electron.

b)Determine the speed of the electron.