A small diamond of mass 15.9 g drops from a swimmer's earring and falls through the water, reaching a terminal velocity of 1.9 m/s.

(a) Assuming the frictional force on the diamond obeys f = −bv, what is b (in kg/s)? (Round your answer to at least four decimal places.)

(b) How far (in m) does the diamond fall before it reaches 90 percent of its terminal speed?

A skydiver of mass 82.0 kg jumps from a slow-moving aircraft and reaches a terminal speed of 49.9 m/s.

(a) What is her acceleration when her speed is 30.0 m/s?

(b) What is the drag force on the skydiver when her speed is 49.9 m/s?

(c) What is the drag force on the skydiver when her speed is 30.0 m/s?

A coil of inductance 120 mH and unknown resistance and a 1.0 μF capacitor are connected in series with an alternating emf of frequency 950 Hz. If the phase constant between the applied voltage and the current is 78°, what is the resistance of the coil?

Identify a practical example of Newton’s law of acceleration. Explain how the example illustrates the law.

Please show work. Thank you!!

Question 3:

1. ) Air contains approximately 80% N₂ and 20% O₂.
   1. At STP, what is the rms speed of O₂ molecules in air?
   2. At STP, what is the average KE of an O₂ molecule?
   3. At STP, what is the rms speed of N₂ molecules?
   4. If we don’t distinguish between N₂ and O₂, what would be the average rms speed?

1. Actual question:) Now consider the same situation as in problem (3) but the 50 cm long rod is half aluminum and half copper. The aluminum end is in boiling water.

1. What would be the steady temperature of the Al-Cu junction?
2. How much ice will the rod melt in 20 minutes.

Firstly, I wasn't sure exactly where to put this. It's a typesetting query but the scope is greater than TEX; however it's specific also to physics and even more specific to this site.

I've recently been reading a style guide for scientific publications (based on ISO 31-11), however there was no mention of quantum mechanical operators. I've seen them written a few ways and was wondering if there was a decision handed down from "up above" that any particular way is best.

H -- I see this most commonly but I suspect it's mostly due to (mild) laziness to not distinguish it from a variable.
H^ -- This is nicer to me because it makes the distinction between operator and variable. From what I understand of the ISO the italic means it's subject to change, which is true of the form of an operator, but not really its meaning? So I'm not totally sure if that's appropriate here.
H -- Roman lettering is used for functions e.g. sinx, erf(x), and even the differential operator (as in ddx) so this seems to me like the most suitable category to put operators in.
H^ -- Probably the least ambiguous but may also be redundant.

Which would be the best to use? Am I being too pedantic?

In nature, is total energy always conserved (yes or no)? Why?

A 10-cm-long thin glass rod uniformly charged to 15.0 nC and a 10-cm-long thin plastic rod uniformly charged to - 15.0 nC are placed side by side, 4.40 cm apart. What are the electric field strengths E1 to E3 at distances 1.0 cm, 2.0 cm, and 3.0 cm from the glass rod along the line connecting the midpoints of the two rods?

Specify the electric field strength E1

Specify the electric field strength E2

Specify the electric field strength E3

Expand 1.00 mol of a monatomic gas, initially at 3.60 kPa and 313 K, from initial volume V_i = 0.723 m³ to final volume V_f = 2.70 m³. At any instant during the expansion, the pressure p and volume V of the gas are related by p = 3.60 exp[(V_i - V)/a], with p in kilopascals, V_i and V are in cubic meters, and a = 2.10 m³. What are the final (a) pressure and (b)temperature of the gas? (c) How much work is done by the gas during the expansion? (d) What is the change in entropy of the gas for the expansion? (Hint: Use two simple reversible processes to find the entropy change.)

1. A 12m window hanging scaffolding basket supporting an 80Kg man and paint material? The scaffolding is hanging by a steel rope at eacch end. The basket weight is 40 Kg, the paint is 25Kg located at the middle. The man is located at the middle.

1. Draw the forces diagram.

2. What are the forces F1 and F2 at the ropes holding the basket at the ends?

b) The man moves 4 meters towards F2, will F1 & F2 change?    

c) Find the new F1 & F2 forces exerted on the scaffolding in b above. ∑Ƭ cw=∑Ƭccw & Ƭ=Fd?

2. Two cars of equal weights of (1400lb each) were subject to an inelastic head-on collision. One car was traveling eastbound at 50mi/h speed and the other car was traveling westbound at 60mi/h speed.   

1. What was the direction of the motion after collision?         

2. What was the speed after collision? m1V1+m2V2=(m1+ m2)V’ ;  

3. How far they went after 1.4 seconds? convert V to ft/s; S=(V)’.(t)

3. Two men exert 115 lb force each to push a car for distance of 150 feet.

1. What is the Work done in lb ft? W=F.S   

2. What is the power exerted after 5 minutes? P=W/t  

3. If the road is at an angle of 15o uphill. What is the mechanical advantage of the road?

4. What is the force of the effort required to move the 1000lb car the 150 ft in c above?

4. A submersible gasoline pump was used to lift 210 gallons/min of gasoline from the bottom of a tank 20 ft below ground level. (One gallon gasoline is 6.3 lb)

1. What is the power rating of the submersible pump? P=W/t= F.S/t    

2. How many gallons can be lifted in 10 minutes?   

5. A 1000 lb box was moved using inclined plane (h=5ft and L=20ft: MA=L/h), a wheel and axle simple machine (wheel diameter is 2 ft and the axle is 0.5 ft: MA=D/d) and 3 pulleys with 3 movables strands.

1. Find the Mechanical Advantage of the inclined plane and the wheel and axle

2. Find the MA of the system (MA = MA1 x MA2 x MA3)

3. Find the exerted effort.

6. True or False questions.

Sitting in a second-story apartment, a physicist notices a ball moving straight upward just outside her window. The ball is visible for 0.24 s as it moves a distance of 1.18 m from the bottom to the top of the window.How long does it take before the ball reappears?What is the greatest height of the ball above the top of the window?

Imperial Building has height of 73 m. Three snipers on a nearby roof shut with three rifle when King Kong jumped down (free fall).
1.
The sniper A shut with initial velocity 20 m/s and angle 30 degree, the horizontal distance from the sniper A to the base of imperial building is 40 m. The roof is 50 m tall.
2.
The sniper B shut with initial velocity 10 m/s and angle 60 degree, the horizontal distance from the sniper B to the base of imperial building is 30 m. The roof is 60 m tall.
3.
The sniper C shut with initial velocity 30 m/s and angle 20 degree, the horizontal distance from the sniper C to the base of imperial building is 50 m. The roof is 70 m tall.

Do a careful investigation, find out Who shut King Kong

An AC generator supplies an rms voltage of 240 V at 50.0 Hz. It is connected in series with a 0.350 H inductor, a 3.60 μF capacitor and a 211 Ω resistor.

1. What is the impedance of the circuit?

2. What is the rms current through the resistor?

3. What is the average power dissipated in the circuit?

4. What is the peak current through the resistor?

5. What is the peak voltage across the inductor?

6. What is the peak voltage across the capacitor?

7. The generator frequency is now changed so that the circuit is in resonance. What is that new (resonance) frequency?

Explain conservation of momentum and give examples in daily life.

In your own words, explain impulse and give examples in daily life.

In your own words, center of mass and give examples in daily life

please reply in text! (not handwritten)

Two point charges, Q1 = 3.3?C and Q2 = -1.5?C ,are placed on the x axis. Suppose that Q2 is placed at the origin, and Q1 is placed at the coordinatex1 = ? 6.0cm (Figure 1) .

Part A:

At what point(s) along the x axis is the electric field zero? Determine the x-coordinate(s) of the point(s).

Express your answer using two significant figures. If there is more than one answer, enter your answers in ascending order separated by commas.

Part B:

At what point(s) along the x axis is the potential zero? Determine the x-coordinate(s) of the point(s).

Express your answer using two significant figures. If there is more than one answer, enter your answers in ascending order separated by commas.