Electron: selection rule, states reached in second order?

An electron exists in its ground state in a one-dimensional box with infinite walls.... see attachmetn

Speed an asteroid

Hi This problem makes me confuse, would you help me abut that: A NASA satellite has just observed an asteroid that is on a collision course with the Earth. The asteroid has an estimated mass, based on its size, of 5 X 10^9 Kg. it is approaching the Earth on a head-on course with a velocity of 600 m/s relative to the Earth and is now 5.0 x 10^6 km away. The average force of air resistance is 3.7 x 10^11 N as the asteroid moves 300 km through the atmosphere. With what speed will it hit the Earth's surface (assume the mass of the asteroid stays constant as it moves through the atmosphere)? Thank you

what was that speed?

Hi I need your help about this problem. Would you help me? A 900 kg Geo collides into the rear end of a 2000 kg Lexus stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 4.5 m before stopping on the horizontal road. The police officer, knowing that the coefficient of kinetic friction between tires and road is 0.40, calculates the speed of the Geo at impact. What was that speed? Thank you I have one more question. Please help me A person rides in an elevator that is falling but is slowing down as it falls. Dose it true; that the force of the elevator floor is doing positive work on the person!?? Thank you agai... click for more

hAMONIC MOTION

A body oscillates with simple harmonic motion along the x-axis.Its displacement varies with time according to the equation x=5(pi/t +pi/3).The velocity(in m/s)of the body at t=1second is? is it V=-5PI M/S SIN(4PI/3)=-13.6 ? note by pi=3.14

Infinite Square Well - Griffith's second edition of Introduction to Quantum Mechanics.

Problem 2.37 A particle in the infinite square well (Equation 2.19) has the intitial wave function ψ(x,0) = Asin³(πx/a) (0≤ x ≤a). Determine A, find ψ(x,t) and calculate as a function of time. What is the expectation value of the energy? Hint: sinⁿθ and cosⁿθ can be reduced, by repeated application of the trigonometric sum formulas, to linear combinations of sin(mθ) and cos(mθ), with m=0,1,2...n.