Physics

posted by .

A 3.0-kg cart is rolling along a frictionless, horizontal track towards a 1.2-kg cart that is held initially at rest. The carts are loaded with strong magnets that cause them to attract one another. Thus, the speed of each cart increases. At a certain instant before the carts collide, the first cart's velocity is +3.9 m/s, and the second cart's velocity is -2.5 m/s. (a) What is the total momentum of the system of the two carts at this instant? (b) What was the velocity of the first cart when the second cart was still at rest?

  • Physics -

    (a) 3.0*3.9 - 1.2*2.5 = 8.7 kg*m/s

    (b) Since TOTAL linear momentum must be conserved at all times before (and after)collision, when cart 2 is motionless, the speed of cart 1 must be 8.7/3.0 = 2.9 m/s.

    Total momentum is conserved because the two carts interact magnetically with EACH OTHER rather than with an external magnet. The two forces on each other cancel.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physics

    Jennifer (mass 58.0 kg) is standing at the left end of a 13.0 m long 594.0 kg cart that has frictionless wheels and rolls on a frictionless track. Initially both Jennifer and the cart are at rest. Suddenly, Jennifer starts running …
  2. physics

    Two carts, one twice as heavy as the other, are at rest on a horizontal frictionless track. A person pushes each cart with the same force for 4.00 s. If the magnitude of the momentum of the lighter cart after the push is P, the magnitude …
  3. physics

    Two carts, one twice as heavy as the other, are at rest on a horizontal frictionless track. A person pushes each cart with the same force for 4.00 s. If the magnitude of the momentum of the lighter cart after the push is P, the magnitude …
  4. physics

    Two carts, one twice as heavy as the other, are at rest on a horizontal frictionless track. A person pushes each cart with the same force for 6.00 s. If the kinetic energy of the lighter cart after the push is K, the kinetic energy …
  5. Physics

    I know I said I didn't know how to start my last question and them figured it out on my own but this one I have tried to work out and really can't get. We have two carts that have magnets to keep them from touching. One cart is initially …
  6. Physics

    Two boys standing on carts that move along a horizontal frictionless surface. The mass of each boy-cart combination is 100 kg, and each moves initially with the velocities of: Boy A 7cm/sec and Boy B: 10cm/sec. The boy on cart A throws …
  7. physics

    A 2.4-kg cart is rolling along a frictionless, horizontal track towards a 1.3-kg cart that is held initially at rest. The carts are loaded with strong magnets that cause them to attract one another. Thus, the speed of each cart increases. …
  8. physics

    Two carts are involved in an elastic collision. Cart A with mass 0.55 kg is moving towards Cart B with mass 0.55 kg, which is initially at rest. Cart A stops after the collision and Cart B begins to move. What is the final kinetic …
  9. Physics

    W have three air carts (labeled #1, #2, and #3) on an air track. The carts are equipped with spring bumpers so that all collisions are elastic. The masses of the carts are m1 = 5m, m2 = 2m, and m3 = m. Initially, cart #1 is given a …
  10. physics

    A 2.9-kg cart is rolling along a frictionless, horizontal track towards a 1.5-kg cart that is held initially at rest. The carts are loaded with strong magnets that cause them to attract one another. Thus, the speed of each cart increases. …

More Similar Questions