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  1. K

    Pool Ball Momentum Question

    That was litterally all of the information they gave to me. In the answer though they have: m1v1 + m2v2 = m1v1` + m2v2` (170g)(3.13m/s) + 0 = (170g)(-0.147 m/s) + (155g)(v2') v2' = 3.59 m/s I really just have no idea where they got the -0.147 m/s
  2. K

    Pool Ball Momentum Question

    Homework Statement Mass of Cue stick : 595 g Mass of White Ball: 170 g Mass of Black Ball: 155 g On the pool table, the white ball bounces off of the black ball and moves in the direction opposite to its original direction. If the speed of the white ball immediately after the collision is...
  3. K

    Wavelength of a photon

    Homework Statement Calculate the shortest wavelength photon that is emitted in the hydrogen atom. Energy when n = 1 = -13.6 eV Homework Equations E = hc/λ λ = hc/E The Attempt at a Solution Well as far as I understand, when the electron is in the n = 1 energy level it has it's...
  4. K

    Electron's Energy After Absorbing A Photon

    Homework Statement An electron in the 3rd stationary state around a hydrogen atom has an energy value of -1.512 eV. What will the electron's energy be if the hydrogen atom absorbs a photon with a wavelength of 1090 nm? E = -1.512 eV Homework Equations Ephoton = hc/λ The Attempt...
  5. K

    Energy Levels and Wavelengths

    Homework Statement In the hydrogen atom, the electron jumps from the n = 1 level to the n = 4 level. a. During this transition from n = 1 to n = 4, is a photon emitted or absorbed? b. What is the change in energy of the electron? c. State the transition in words. d. What is the wavelength...
  6. K

    Millikan Oil Drop Experiment Question

    Okay, I understand! Thank you for your help!
  7. K

    Millikan Oil Drop Experiment Question

    If I divide that charge by 1.60 x 10^-19 C I get 72.0207 electrons. Does it have to be a whole number?
  8. K

    Millikan Oil Drop Experiment Question

    Homework Statement A 1.50 x 10^-14 kg oil drop accelerates downward at a rate of 1.80 m/s^2 when placed between two horizontal plates that are 9.40 ch apart. The potential difference between the two plates is 980 V. Determine the magnitude of the charge on the oil drop. m = 1.50 x 10^-14 kg...
  9. K

    Young's Experiment and the Wave-Particle Model

    Homework Statement How do the results of performing Young's experiment with x-rays and then high speed electrons support the wave-particle model? The Attempt at a Solution The experiment showed that an electron traveling at high speeds are capable of making interference patters, which is a...
  10. K

    Compton Effect, frequency question

    Nevermind! I got it now! :D Thanks :)
  11. K

    Compton Effect, frequency question

    Hmm... I'm not sure what I'm doing wrong then...
  12. K

    Compton Effect, angle of deflection

    Homework Statement The scientist changes the frequency of the incident X-ray to 4.50 x 10^19 Hz and measures the deflected X ray frequency of 4.32 x 10^19 Hz. What was the angle of deflection? Fi = 4.50 x 10^19 Hz Ff = 4.32 x 10^19 Hz Homework Equations Δλ = λf - λi Δλ =...
  13. K

    Compton Effect, frequency question

    Wait... was your λf value 1.06771397 x 10^-12 ?? My calculator was in radian mode...
  14. K

    Compton Effect, frequency question

    Homework Statement An X-ray with a frequency of 3.74 x 10^20 Hz is incident on a thin piece of metal. The lower frequency X ray on the other side is observed deflected at 48°. What is the frequency fo the deflected X ray? fi = 3.74 x 10^20 Hz Deflected at 48° Homework Equations I'm...
  15. K

    HELP EMR wavelength question!

    Homework Statement To confirm the wavelength of a new laser, a scientist prepares a diffraction grating with a distance of 5.00 x 10^-6 m between slits and places it in front of the laser which is 1.50 m in front of a screen. The scientist measures the distance from the central maxima to the...
  16. K

    Magnetic Field Problem!

    Thank you very much! I really appreciate your advice as well. :)
  17. K

    Magnetic Field Problem!

    Homework Statement An electron (m= 9.11 x 10^-31 kg) enters a downward magnetic field of 5.00 x 10^-1 T with a velocity of 6.50 x 10^6 m/s West. Calculate the radius of the circular path it will follow when it is traveling within the magnetic field. m = 9.11 x 10^-31 kg v = 6.50 x 10^6...
  18. K

    Electric Field Question!

    Homework Statement A particle has a charge of -5.00 \muC. At a point near this particle, the electric field strength is 7.2 x 10^7 N/C. Determine the distance from this point to the charged particle. q = -5.00 x 10^-6 C E = 7.2 x 10^7 N/C k = 8.99 x 10^9 Nm^2/C^2 Homework Equations E...
  19. K

    Applying Coulomb's Law

    Homework Statement What is the distance between two charges of -5.00 C each if the force of electrostatic repulsion acting on them is 4.00 x 10^3 N? q1 = -5.00 C q2 = -5.00 C Fe = 4.00 x 10^3 k = 8.99 x 10^9 Nm^2/C^2 Homework Equations Fe = kq1q2/r^2 The Attempt at a Solution...
  20. K

    Conservation of Momentum of a shot bullet

    Homework Statement If a 30 g bullet is shot with a velocity of +300 m/s from a 7.5 kg gun, what is the recoil velocity of the gun? m1 = 0.03 kg v1 = 300 m/s m2 = 7.5 kg Velocity initial for both objects is 0.0 m/s Homework Equations (m1 + m2)(v) = (m1v1) + (m2v2) The Attempt...
  21. K

    Tension in cord at 30.0 degrees

    Homework Statement A 0.160 kg ball attached to a light cord is swung in a vertical circle with a radius of 70.0 cm. At the top of the swing, the speed of the ball is 3.26 m/s. The center of the circle is 1.50 m above the floor. Determine the magnitude of the tension in the cord when the...
  22. K

    Energy, Efficiency Question

    The ratio of the output (useful work) to the input (total energy used) I read that regardless of speed, both the slow and fast chairlifts have identical efficiency, but I don't understand this.
  23. K

    Energy, Efficiency Question

    Homework Statement The energy lost operating a low-speed chairlift is the same as the energy lost operating a high-speed lift of equal path length. What happens to the efficiency when you change from a low speed to a high speed chairlift? Homework Equations We know that high speed...
  24. K

    Energy Transfer of chairlift

    Homework Statement Propose an explanation for the following fact. Include a description of the energy transfers that would take place when the lift starts and stops. A fully loaded chairlift requires more energy to start then it does to maintain motion. The Attempt at a Solution I...
  25. K

    Energy Question Please Help

    Oh duh! That was dumb of me! Thank you so much!
  26. K

    Energy Question Please Help

    Energy Question! Please Help! Homework Statement A 170g hockey puck sliding at 25 m/s slows to a speed of 10 m/s in a distance of 7.5m. Determine the force of friction causing the puck to slow down. m=170g = 0.170kg V1 = 25 m/s V2= 10 m/s d = 7.5 m/s Homework Equations Kinetic Energy =...