- estimate the energy (in joule) produced from radioactivity over the Earth's lifetime.

- Estimate the energy density (in joule/kg) of nuclear fission fuels.

- Estimate mass (in kg) of radioactive material is need to power Earth’s interior over its lifetime.

- Estimate the mass of Earth (in kg).

- Estimate the fraction of Earth's mass in radioactive material.

Consider the 1D wave equation d^2u/dt^2 = c^2( d^2u/dx^2) with the following boundary conditions: u(0, t) = ux (L, t) = 0 . (a) Use separation of variables technique to calculate the eigenvalues, eigenfunctions and general solution. (b) Now, assume L = π and c = 1. With initial conditions u(x, 0) = 0 and ut(x, 0) = 1, calculate the solution for u(x, t). (c) With initial conditions u(x, 0) = sin(x/2) and ut(x, 0) = 2 sin(x/2) − 3 sin(5x/2) calculate the solution for u(x, t).

A circuit is constructed with an AC generator, a resistor, capacitor and inductor as shown. The generator voltage varies in time as ε =V_a - V_b = ε_msinωt, where ε_m = 120 V and ω = 231 radians/second. The inductance L = 155 mH. The values for the capacitance C and the resistance R are unkown. What is known is that the current in the circuit leads the voltage across the generator by φ = 49 degrees and the average power delivered to the circuit by the generator is P_avg = 106 W.

What is I_max, the amplitude of the current oscillations in the circuit?

What is R, the value of the resistance of the circuit?

What is C, the value of the capacitance of the circuit?

The value of ω is now changed, keeping all other circuit parameters constant, until resonance is reached. How was ω changed?

ω was decreased

ω was increased

What is the average power delivered to the circuit when it is in resonance?

Four identical charges (+2.0 ?C each) are brought from infinity and fixed to a straight line. The charges are located 0.40 m apart. Calculate the amount of work done in assembling the charges.

1) What are a Vande Graaf generator and a Tesla Coil? Why aren’t people hurt when they come in contact with such high voltage?

2) What is the difference between AC and DC? Three prong and two prong plugs? 110 and 220 plugs?

A 2.25×10⁴ N elevator is to be accelerated upward by connecting it to a counterweight using a light (but strong!) cable passing over a solid uniform disk-shaped pulley. There is no appreciable friction at the axle of the pulley, but its mass is 875 kg and it is 1.50 m in diameter.

How heavy should the counterweight be so that it will accelerate the elevator upward through 6.00 m in the first 4.00 s , starting from rest?

Under these conditions, what is the tension in the cable on elevator side of the pulley?

Under these conditions, what is the tension in the cable on counterweight side of the pulley?

I posted this before but 3000 wasnt the correct answer

Three point charges are arranged as follows: Charge Q1 = + 5.00 nC is located at the origin. Charge Q2 = -3.00 nC is located at x = +4.00 cm, y = 0 cm. Charge Q3 = + 6.00 nC is at x = 0 cm, y = -3.00 cm. a. What is the net electric field at point P with coordinates x = 4.00 cm, y = -3.00 cm?

(i) Express your answer as a vector in i, j, k notation.

(ii) Express your answer as the total magnitude and direction θ from the +x-axis. b. What is the net electric force on an proton placed at point P? Express your answer only in terms of magnitude and direction.

c. What is the acceleration of this proton? Express your answer only in terms of magnitude and direction. Mass of the proton is 1.673∙10-27 kg.

What starts a dislocation and how does this advance in a crystal structure?

This question is about throwing a ball vertically upwards and catching the ball.

Compare the part of the graph of mechanical energy vs. time before the ball is in free-fall to the part while the ball is in free fall. Carefully explain, using the concept of work done on the system, why the ball’s mechanical energy changed as it did.

Think of a Newtonian cradle made of only two marbles. These two marbles of masses m1 and m2 are each suspended by identical strings. The strings are initially both vertical so the marbles are touching each other when undisturbed. The marble with m1 is shifted away from the initial position until is reaching the height h1 while the length of the string does not change and then is set free to fall and collide with marble m2. What is the formula for the height which both marbles will reach after the collision if: a). The collision is elastic; b). The collision is inelastic; (c). What will be the heat developed during the collision in both cases?Hint: when the marbles collide, all vectors velocity are orientated along the same axis.

Needs to document an amusement park ride. For example: Round rotating cylinder where the floor drops out. The information can come from any online website. Needs to know the radius and speed at which the ride needs to rotate so that you don't fall?

Calculate the coefficient of static friction for this ride also

Aliens are observing a park in new york. They notice a merry-go-round has a radius of 3.12m and a moment of inertia of 3100kgm^2 at the vertical axis through the center. The contraption has been lubricated recently so there is no friction. one of the earthlings applies a tangential force of 19N for 13s begging at rest. Unfortunaley after gathering this data the aliens computer broke so now they must calculate the work that was done over the course of the 13s.