A cart of mass m is moving with negligible friction along a track with known speed v1 to the right. It collides with and sticks to a cart of mass 4m moving with known speed v2 to the right. Which of the two principles, conservation of momentum and conservation of mechanical energy, must be applied to determine the final speed of the carts, and why?
a. Only conservation of momentum because the momentum lost by one cart is gained by the other and there is only one unknown quantity.
b. Both conservation of mechanical energy and conservation of momentum, because both principles apply in any collision.
c. Either conservation of momentum or conservation of mechanical energy, because only one equation is required to solve for the one unknown variable.
For the system of two carts, there is no net external force during their collision, therefore, the total linear momentum of the system is conserved. Further being an inelastic collision, the total kinetic energy will not be conserved.
Answer (a)
A cart of mass m is moving with negligible friction along a track with known speed...