Suppose the straight-line distance between New York and San Francisco is 4.1 × 106 m (neglecting the curvature of the earth). A UFO is flying between these two cities at a speed of 0.68c relative to the earth. What do the voyagers aboard the UFO measure for this distance?

The total energy of an object is 7.86 × 10¹² J, and its kinetic energy is 6.00 × 10¹² J. What is the mass m of the object?

A radar antenna is rotating and makes one revolution every 25 s, as measured on earth. However, instruments on a spaceship moving with respect to the earth at a speed v measure that the antenna makes one revolution every 45 s. What is the ratio v/c of the speed v to the speed c of light in a vacuum?

As observed on earth, a certain type of bacteria is known to double in number every 24 hours. Two cultures of these bacteria are prepared, each consisting initially of one bacterium. One culture is left on earth and the other placed on a rocket that travels at a speed of 0.932c relative to the earth. At a time when the earthbound culture has grown to 16 bacteria, how many bacteria are in the culture on the rocket, according to an earth-based observer?

1. Suppose that the Earth was thermally insulated from the rest of the universe so that it was an isolated system. Describe the entropy of the Earth as a function of time.

2. Consider taking two identical ice cubes out of the freezer. You place one in a cup and let it melt; you take the other and smash it with a hammer and then put it in an identical cup and allow it to melt. Compare the entropy changes of the two ice cubes.

3. Upon freezing, water becomes more orderly and its entropy decreases. Explain why this process does not violate the second law of thermodynamics.

Ip= 19A at Vp = 440V and Vs= 9000V. If the transformer is 95% efficient, how many turns are in the secondary coil? (efficiency e is the ratio of the power output to the power input or e = Ps/Pp). I know the result is Ns= (Vs Np) / Vp = 3680 turns, but why can't I use this below equation:

Ps/Pp = (Is Vs) / (Ip Vp) = 0.95

Is/Ip = Np/Ns

we have Np Vs / Ns Vp = 0.95

Ns= (Vs Np) / (0.95 Vp)

So why can't I use this equation [ Ns= (Vs Np) / (0.95 Vp) ] to find secondary coil.
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Could you please draw a diagram of this case. Please explain why I = 240V / (R + r) ? Where does r come from and what formula is this? a 240-V dc motor has an armature whose resistance is 1.8 ohms. When running at its operating speed, it draws a current of 14.0 A. Starting current is 133 A. What series resistance would be required to limit the starting current to 26.0 A? Could you also explain what is a back emf with simple definition? why does it act against applied voltage and reduce the current?

. On a horizontal, frictionless surface, a 9.00 kg object initially moving east at 4.00 m/s collides with a 3.00 kg object that was initially moving north at 10.0 m/s. After the collision, the three-kilogram object moves with a velocity o 12.00 m/s directed 32.0o north of east. (a) Calculate the velocity of the nine-kilogram object after the collision, and (b) determine by calculation the type of collision that occurred.

a) Radon undergoes alpha decay with a half-life of 3.8 days. What is its decay constant in s^-1?

b) Sr -90 (A=90, Z = 38) decays via β^- decay. Calculate the energy of the antineutrino (in keV) if the beta particle has a kinetic energy of 397 keV. Note - you can look the atomic masses up online.

c) What is the average binding energy per nucleon for Argon-40 (A=40, Z = 18) in MeV/nucleon? Note - keep 4 significant figures.

The 1.2 liter coffee pot is filled with 15 ° C water. What is the amount of heat used to heat and boil water when 50 cm3 of water is known to have evaporated? (Do not ignore the changed water density as the temperature changes. Water density 1000 kg / m3).

In the arrangement above, charge A is -46 nC, while charges B and C are each 67 nC.Each side of the triangle is 7.7 cms. Determine the magnitude of the electric field at the center of the triangle, in N/C.

What is the direction of the electric field in the previous problem? Express your answer in degrees measured counterclockwise from the positive x-axis.

briefly describe and explain the electronic polarization of non-metal materials or media upon light transmission, and elaborate its relationship with the electrical and magnetic properties in materials. Use schematics or equations if necessary

In a police rifle test, a 15-g bullet traveling 213 m/s in a vertical direction suddenly buries itself in a 2.4-kg block of wood at rest directly above it. As a result, the bullet-block combination moves vertically upward.

(a) Determine the velocity of the bullet-block combination just after the impact.

(b) Determine the maximum height reached by the bullet/block combination.

(c) Is kinetic energy conserved in this collision?   

Planets X, Y, and Z have circular orbits around a Star, which is similar to our own Sun. Given the data listed below, answer the following questions.

Note: "Days" are treated as "Earth days", thus having 24 hrs.

a) Use the data for Planet X to calculate the mass of this star.  

b) Use the data of of Planet Y to determine its period.

c) Use the data of Planet Z to determine its orbital radius.

A uniform, solid sphere of radius 5.00 cmand mass 1.75 kgstarts with a purely translational speed of 3.25 m/sat the top of an inclined plane. The surface of the incline is 1.75 mlong, and is tilted at an angle of 24.0∘with respect to the horizontal. Assuming the sphere rolls without slipping down the incline, calculate the sphere's final translational speed ?2at the bottom of the ramp.

A proton travels through uniform magnetic and electric fields. The magnetic field is in the negative x direction and has a magnitude of 3.50 mT. At one instant the velocity of the proton is in the positive y direction and has a magnitude of 1830 m/s. At that instant, what is the magnitude of the net force acting on the proton if the electric field is (a) in the positive z direction and has a magnitude of 5.10 V/m, (b) in the negative z direction and has a magnitude of 5.10 V/m, and (c) in the positive x direction and has a magnitude of 5.10 V/m?

1. Plot a graph of Table 2. Consider which variable (voltage or current) should be on the x and y axes.
2. What is the relationship between voltage and current? Use data from your graph to support your answer.
3. Estimate the slope of the linear line and record it in Table 3.
4. How does the value of the slope compare to the resistance you measured? Calculate the percent difference.
5. Use the results of your experiment to verify Ohm’s Law.

A 2kg block slides down a surface inclined at 30 degrees. In traveling 50cm its speed changes from 1 to 2 m/s. Find the work done by gravity and coefficient of kinetic friction?

purpose of the condenser in a refrigeration system? a) rejects heat from refrigerant b)absorbs heat into the refrigerant c) rejects heat from the condensing medium d) increases pressureand temp of the refrigerant