A 45.4 kg, 3.8 m uniform ladder leans against a frictionless wall. A 99.1 kg person is standing on the ladder down 1.04 m from the top of the ladder. The ladder makes an angle of 50 degrees with the horizontal. What is the minimum coefficient of static friction between the ladder and the ground so that the ladder does not slip?

A very metal train moving at a constant speed is passing a hippie observer on a platform. On one of the train cars, a Deathcore guitarist is continually hammering out a note at a frequency of 450 Hz. After the guitarist has passed, the hippie hears the sound with a frequency of 420 Hz. What is the speed of the train?

Please explain work, I always rate!!:)

In an industrial cooling process, water is circulated through a system. If water is pumped with a speed of 4.00 m/s under a pressure of 6.70 × 10⁵ Pa from the first floor through a 3.70-cm diameter pipe, what will be the pressure on the next floor 3.90 m above in a pipe with a diameter of 2.00 cm?

The water flow rate for a particular sprinkler is 18 gpm. The water must be projected at least 22 feet in radius. The sprinkler is mounted 10 feet above the ground and is aimed at an angle of 29 degrees above the horiztonal. With what velocity must the water leave the sprinkler? What diameter (inches) should the opening be to achieve this velocity?

Water Velocity = ft/s

Diameter Opening =  inches

What is the smallest area of ice 29 cm thick that will support a 85 kg man? The ice is floating in freshwater.

Billiard ball A of mass mA = 0.116 kg moving with speed vA = 2.80 m/s strikes ball B, initially at rest, of mass mB = 0.135 kg . As a result of the collision, ball A is deflected off at an angle of θ′A = 30.0∘ with a speed v′A = 2.10 m/s, and ball B moves with a speed v′B at an angle of θ′B to original direction of motion of ball A. Solve these equations for the speed, v′B, of ball B after the collision. Do not assume the collision is elastic.

1. what Connects claim to theory in rotational motion
   1. Includes theoretical model for rotational inertia of a two object system
   2. Discusses similarity and differences between theoretical and experimental models
2. Discusses possible assumptions and limitations with possible impact on claims
3. Suggest improvements

1. Discuss how a missing atom at a lattice side contributes to the conductivity of a semiconductor     

2. Estimate the energy of a photon of X rays. (Answer: 12 keV)

3. On the one hand, we say that electrons in atoms have discrete energies; on the other hand, we say that there is inherent uncertainty in our ability to measure energies. Is there a conflict here?

4. You have just calculated the number density of p-carriers in undoped germanium, a semiconductor, at room temperature. Is it necessary to make a second calculation to find the number density of free electrons?

5. Estimate the energy of a photon of visible light. (Answer: 2.4 eV)

Suppose that a cannon tower of 1000 feet height was erected at the origin of the coordinate space. The speed of the cannonballs launched by the tower is 1000 feet per second. An armored vehicle is patrolling in a circular path around the tower 8000 feet away at a speed of 10 feet per second. Coordinates was chosen such that at time zero the location of the vehicle is (8000, 0, 0).

(a) Describe the motion of the vehicle with a vector valued function with respect to time t.

(b) At time zero, a cannonball is launched from the tower in the direction of u = <u₁,u₂,u₃>, where ||u|| = 1. Ignoring all resistive forces, describe the motion of the cannonball with a vector valued function with respect to time t. Gravitational acceleration g = 32 ft/s².

(c) Determine whether it is possible for the cannonball to hit the vehicle. If it is, find the direction in which the cannonball should be launched, and express your answer as a unit vector.

In a particular frame of reference a virtual particle appears to travel at a speed twice the speed of light. How fast must a different frame move in order for this particle to appear to move instantaneously?

Using words, explain the laws of physics behind this in a paragraph. Don't just write equations with few words.

Here is the video: https://www.youtube.com/watch?v=8B_6BU7SYf8

The Horo was used by the Ancient Japanese to deflect arrows from enemies. Explain how such silk could stop the arrows. The video itself explains it little but please expand on that more and use equations/formulas (like perhaps one for KE) to aid the explanation.

Describe the physics of an electric generator with relevant equations ?

1. For what kinetic energy is the de Broglie wavelength of an electron equal to its Compton wavelength? Express your answer in units of mc2 in doing the calculation, and then use mc2 = 0.5 MeV.(Answer: 0.2 MeV)

2. A beam of electrons with energy 1.0 eV approaches a potential barrier with U = 2.0 eV, whose width is 0.10 nm (see a figure below). Estimate the fraction of electrons that tunnel through the barrier. (Hint: use the relation of probability and the wave function, and the expression for wave function for barrier penetration)

3. Calculate the Fermi energy of sodium (n= 2.65·10^28 m^-3). This metal has a single valence electron per atom.(Answer: 3.25 eV.)

Make a list of all the possible sets of quantum numbers that an electron in an atom can have if n = 4. How many different states with n = 4 are there? Indicate on your list which states are degenerate (i.e. have the same energy as other n = 4 states). Assume that the electron is in a multi-electron atom (i.e. not the Hydrogen atom). Does the total number of states agree with the general rule that the number of states is equal to 2n^2.

You sign up for a bungee jump off a tall bridge. A thick rope with a fixed length of 18.0 m is tied to the bridge, and a bungee cord with an unstretched length of 11.0 m is then connected to the rope. The other end of the bungee cord is attached to your legs.

You step off the bridge, falling from rest. The bungee cord does not start exerting any force on you until you have fallen a distance of 29.0 m (the sum of the rope's length and the unstretched length of the bungee cord). After that, it exerts an upward force on you that eventually brings you to rest, for an instant. Assume the bungee cord, when stretched, acts like an ideal spring, and take g = 10 N/kg, to make the calculations easier. Your mass is 50.0 kg.

You fall a total distance of 54.0 m before coming instantaneously to rest. Determine the spring constant of the bungee cord.
_______ N/m

Part (b)

You sign up for a bungee jump off a tall bridge. A thick rope with a fixed length of 18.0 m is tied to the bridge, and a bungee cord with an unstretched length of 11.0 m is then connected to the rope. The other end of the bungee cord is attached to your legs.

You step off the bridge, falling from rest. The bungee cord does not start exerting any force on you until you have fallen a distance of 29.0 m (the sum of the rope's length and the unstretched length of the bungee cord). After that, it exerts an upward force on you that eventually brings you to rest, for an instant. Assume the bungee cord, when stretched, acts like an ideal spring, and take g = 10 N/kg, to make the calculations easier. Your mass is 50.0 kg.

You fall a total distance of 54.0 m before coming instantaneously to rest, but how far below the bridge are you when you reach maximum speed?
_______ m

Part (c)

You sign up for a bungee jump off a tall bridge. A thick rope with a fixed length of 18.0 m is tied to the bridge, and a bungee cord with an unstretched length of 11.0 m is then connected to the rope. The other end of the bungee cord is attached to your legs.

You step off the bridge, falling from rest. The bungee cord does not start exerting any force on you until you have fallen a distance of 29.0 m (the sum of the rope's length and the unstretched length of the bungee cord). After that, it exerts an upward force on you that eventually brings you to rest, for an instant. Assume the bungee cord, when stretched, acts like an ideal spring, and take g = 10 N/kg, to make the calculations easier. Your mass is 50.0 kg.

You fall a total distance of 54.0 m before coming instantaneously to rest. Calculate the maximum speed you reach during the fall.
_______ m/s