Recent content by EndoBendo

  1. E

    Solving a 24-Car Train Acceleration Problem

    v must be in m/s to get to Newtons i included part 2 , i got 1.98. is that right??
  2. E

    Solving a 24-Car Train Acceleration Problem

    Homework Statement A locomotive accelerates a 24-car train along a level track. Every car has a mass of 50000 kg and is subject to a frictional force f = 250 v, where the speed v is in meters per second and the force f is in Newtons. At the instant when the speed of the train is 28 km/h...
  3. E

    How Fast Must a Juggler Throw Four Balls?

    Homework Statement A juggler is able to handle four balls simultaneously. He takes 0.5 s to cycle each ball through his hands, throw the ball, and be ready to catch the next ball. (a) With what velocity must he throw each ball up? (b) What is the position of the other three balls when he...
  4. E

    What Happens to the Remaining Support When One Is Removed From a Supported Rod?

    Homework Statement A uniform thin rod of weight W = 100 N is supported horizontally by two vertical props at its ends. At time t = 0 one of the these supports is kicked out. Find the force on the other support immediately thereafter. Homework Equations F1 + F2 = mg The Attempt...
  5. E

    Torque/Rotational Dynamics HW Problem

    Ok , I have a new guess now lol... 100N, since it is the only remaining force acting in the + y direction
  6. E

    Rotational motion/conservation HW problem

    many thanks! I just wanted to make sure i wasnt crazy lol
  7. E

    Torque/Rotational Dynamics HW Problem

    Homework Statement A uniform thin rod of weight W = 100 N is supported horizontally by two vertical props at its ends. At time t = 0 one of the these supports is kicked out. Find the force on the other support immediately thereafter. Homework Equations Sum of forces?? The...
  8. E

    Centripetal Acceleration/Rotational Motion HW Problem

    sorry i meant 3.62 for the new value lol
  9. E

    What Is the Velocity of a Massless Ping-Pong Ball After an Elastic Collision?

    An "infinitely massive" Ping-Pong paddle moving with a velocity of 20 m/s hits a "massless" Ping-Pong ball at rest. The collision is elastic. What is the velocity of the ball after the collision? i get v2f = (2(infinite mass)/(infinite mass - 0))*20m/s = 40m/s is this correct?? i don't...
  10. E

    Centripetal Acceleration/Rotational Motion HW Problem

    A block sits at the top of a smooth sphere of radius 1m. Suddenly, under the force of gravity, It begins to slide down the surface of the sphere until it leaves the surface. At what speed does it leave the surface? mgcosθ + N = mv^2/R But N =0 v^2 = Rgcosθ V^2 = gcosθ speed = v = (...
  11. E

    Rotational motion/conservation HW problem

    A horizontal vinyl record of mass 0.10 kg and radius 0.1 m rotates freely about a vertical axis through its center with an angular speed of 4.7 rad/s. The rotational inertia of the record about its axis of rotation is 0.0005 kg*m^2. A wad of wet putty of mass 0.020 kg drops vertically onto the...