A 16.5-μμF capacitor is charged to a potential of 60.0 V and then discharged through a 75.0­ ΩΩ resistor.

1)

How long after discharge begins does it take for the capacitor to lose 90.0% of its initial charge? (Express your answer to three significant figures.)

answer .....ms

How long after discharge begins does it take for the capacitor to lose 90.0% of its initial energy? (Express your answer to three significant figures.)

answer .....ms

What is the current through the resistor at the time when the capacitor has lost 90.0% of its initial charge? (Express your answer to three significant figures.)

answer .....mA

What is the current through the resistor at the time when the capacitor has lost 90.0% of its initial energy? (Express your answer to three significant figures.)

answer ....mA

Projectile Motion 2D

A batter hits a ball with initial speed 20m/s at a launch angle of 60

A hollow, thin-walled sphere of mass 11.0 kg and diameter 48.0 cm is rotating about an axle through its center. The angle (in radians) through which it turns as a function of time (in seconds) is given by θ(t)=At2+Bt4, where A has numerical value 1.20 and Bhas numerical value 1.60.

At the time 3.00 s , find the angular momentum of the sphere.

At the time 3.00 s , find the net torque on the sphere.

Most of us know intuitively that in a head-on collision between a large dump truck and a subcompact car, you are better off being in the truck than in the car. Why is this? Many people imagine that the collision force exerted on the car is much greater than that exerted on the truck. To substantiate this view, they point out that the car is crushed, whereas the truck is only dented. This idea of unequal forces, of course, is false; Newton's third law tells us that both objects are acted upon by forces of the same magnitude. The truck suffers less damage because it is made of stronger metal. But what about the two drivers? Do they experience the same forces? To answer this question, suppose that each vehicle is initially moving at 6.40 m/s and that they undergo a perfectly inelastic head-on collision. Each driver has mass 72.0 kg. Including the masses of the drivers, the total masses of the vehicles are 800 kg for the car and 4,000 kg for the truck. If the collision time is 0.100 s, what force does the seat belt exert on each driver? force on truck driver N force on car driver N

A large boulder is ejected vertically upward from a volcano with an initial speed of 40.7 m/s . Air resistance may be ignored. A) At what time after being ejected is the boulder moving at a speed 20.3 m/s upward? B) At what time is it moving at a speed 20.3 m/s downward? C)When is the displacement of the boulder from its initial position zero? D)When is the velocity of the boulder zero? E)What is the magnitude of the acceleration while the boulder is moving? F)What is the direction of the acceleration while the boulder is moving? (up or down)

Throw a ball so that it is projected vertically upward. Catch it at the same height it was released. Have a partner measure the time the ball is in the air - that is, from the time of release to the time the ball lands in your hand.

Throw a ball so that it is projected vertically upward. Catch it at the same height it was released. Have a partner measure the time the ball is in the air - that is, from the time of release to the time the ball lands in your hand.
Determine the velocity of the ball at the moment of release and the distance the ball traveled before it started its descent. Graph the flight of the ball into five sections: (1) from initiation of upward motion of the hand to just prior to release, (2) from moment of release to just before maximum height, (3) at maximum height, (4) from maximum height to just before you catch the ball, (5) from the ball contact to the ball being brought to rest. For each section, describe the displacement, velocity, and acceleration.

Determine the velocity of the ball at the moment of release and the distance the ball traveled before it started its descent. Graph the flight of the ball into five sections: (1) from initiation of upward motion of the hand to just prior to release, (2) from moment of release to just before maximum height, (3) at maximum height, (4) from maximum height to just before you catch the ball, (5) from the ball contact to the ball being brought to rest. For each section, describe the displacement, velocity, and acceleration.

A point particle with charge

q = 4.2 ?C

is placed on the x axis at

x = ?10 cm

and a second particle of charge

Q = 7.8 ?C

is placed on the x axis at

x = +25 cm.

(a) Determine the x and y components of the electric field due to this arrangement of charges at the point

(x, y) = (10, 10)

(the units here are centimeters).

(b) Determine the magnitude and direction of the electric field at this point.

1. A train moving at a constant speed of 52.0 km/h moves east for 38.0 min, then in a direction 45.0° east of due north for 21.0 min, and then west for 65.0 min. What is the average velocity of the train during this run? a) magnitude- km/h b) ° (counterclockwise from east) 2. A golf ball is struck at ground level. The speed of the golf ball as a function of time is shown in the figure below, where t = 0 at the instant the ball is struck. The graph is marked in increments of 0.25 s along the time axis, and vmin = 18.60 m/s and vmax = 22.27 m/s. (Values in figure do not necessarily match values in problem). a) How far does the golf ball travel horizontally before returning to ground level? b) What is the maximum height above the ground level attained by the ball? 3. A projectile's launch speed is 3.1 times its speed at maximum height. Find launch angle ?0. 4. In the figure, a ball is thrown leftward from the left edge of the roof, at height h above the ground. The ball hits the ground 1.37 s. later, at distance d = 20.5 m from the building and at angle ? = 56° with the horizontal. a) Find h= m b) What is the velocity at which the ball is thrown? Magnitude= m/s Angle= ° relative to the horizontal c) Is that angle above or below the horizontal? Above/below

A film of oil lies on wet pavement. The refractive index of the oil exceeds that of the water. The film has the minimum nonzero thickness such that it appears dark due to destructive interference when viewed in red light (wavelength = 640.0 nm in vacuum). Assuming that the visible spectrum extends from 380 to 750 nm, for which visible wavelength(s) in vacuum will the film appear bright due to constructive interference?

The great russian physicist Lev Landau developed a famous entry exam to test his students. This "Theoretical Minimum" contained everything he considered elementary for a young theoretical physicist. Despite its name, it was notoriously hard and comprehensive, and in Landau's time, only 43 students passed it.

I wonder if anyone can provide the list of topics, or even a copy of the exam?

(I'm sure I'd have no chance to pass, but I'd like to see it out of a sense of sportmanship ;-). Also, I think it would make quite a good curriculum of theoretical physics (at least pre 1960).)

What type of motion is occurring when the slope of a velocity vs. time graph is zero? Also, what type of motion is occurring when it's not zero

1. What is nanophotonics? Give an example of a manifestation of nanophotonics.

2. What are free carriers in plasmonic semiconductor nanocrystals?

3. What is the main difference between surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR)?

please answer ALL THREE questions with detailed answers! please have legible handwrtting if handwritten.

Thank you!!!

A 35-year-old patent clerk needs glasses of 50-cm focal length to read patent applications that he holds 25 cm from his eyes. Five years later, he notices that while wearing the same glasses, he has to hold the patent applications 40 cm from his eyes to see them clearly.

What should be the focal length of new glasses so that he can read again at 25 cm?

Draw band structure diagrams for the following, highlighting on each diagram the valence band, conduction band and the band gap.

(a) Au,

(b) SiO2

(c) intrinsic Ge

(d) p-type Ge

(e) n-type Ge

On each of the band diagrams also indicate the probable location of the Fermi level for (c), (d) and (e) at a temperature of 0 K.

1)An object of mass m = 0.25kg has a horizontal spring attached to its left side, and

slides along a frictionless surface. The spring constant is ? = 0.4 N . At t = 0s, the m

object is displaced 0.1m to the right of its equilibrium position. Its initial velocity is 0.4 m , toward the right.

a) What is the period T of the motion?

b) What is the angular frequency ? ?

c) What is the frequency ? ?

d) What is the total energy E ?

e) What is the amplitude A of the motion? (careful!)

f) What is the phase angle ? ?

g) What is the maximum velocity vmax? (careful!)

h) What is the maximum acceleration amax ?

i) What are the position, velocity, and acceleration at t = ? s?

2)A simple pendulum has a period of 2.40s at a place where g = 9.810 m/s^2 What is the
value of g at another place where this pendulum has a period of 2.41s?

3)A wave travels along a string of linear mass density