If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Conservation of linear momentum

You might need: Calculator


A marble launcher is affixed to the top of the cart which is resting on a horizontal surface. A marble of mass M is inserted into the tube, and the spring is compressed and locked in place. While at rest, the spring is released, and the marble is launched with a velocity of 12m/s. The mass of the launcher and cart is 25M.
A diagram shows a marble launcher attached to a cart before and after the marble is launched. A black circle represents the marble. Before launch, the marble is shown inside the launcher, which is a horizontal cylinder with a compressed spring. After launch, the marble is shown directly to the right of the launcher. The spring inside the launcher is no longer compressed. An arrow above the marble points to the right and is labeled twelve meters per second. An arrow above the cart and launcher, labeled V, points to the left.
Calculate the velocity of the cart and empty launcher after the marble is released.
Write your answer to two significant figures.
  • Your answer should be
  • an integer, like 6
  • an exact decimal, like 0.75