Conservation of momentum in collisions

Answer Key - Grade 11 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   East is positive. A 1.5 kg cart at 6 m/s hits a 0.5 kg cart moving at 0 m/s, and they stick together. What is their velocity after, Ari?

   4.5 m/s
2. 2.

   East is positive. A 2.5 kg cart at 4 m/s hits a 1.5 kg cart moving at -2 m/s, and they stick together. What is their velocity after, Bo?

   1.75 m/s
3. 3.

   East is positive. A 4 kg cart at 3 m/s hits a 2 kg cart moving at 1.5 m/s, and they stick together. What is their velocity after, Esme?

   2.5 m/s
5. 4.

   In the momentum bar chart, what is the joined carts' momentum after, Jun?

   • 8 kg·m/s
   • 0, since they stuck
   • 6 kg·m/s
   • 10 kg·m/s
6. 5.

   In the momentum bar chart, what is the joined carts' velocity after, Kira?

   Use the picture in question 4.

   • 1.5 m/s east
   • 6 m/s east
   • 0 m/s, since they stuck
   • 3 m/s east
7. 6.

   Two carts at rest are pushed apart by a spring. What is their total momentum afterward, Milo?

   • The sum of both speeds
   • Equal to the spring's force
   • 0 kg·m/s
   • More than before
8. 7.

   A 1 kg cart and a 3 kg cart are pushed apart from rest. Which moves faster, Noah?

   • The 1 kg cart, 3 times as fast
   • The 3 kg cart
   • They move equally fast
   • Neither moves
9. 8.

   From rest, a 1 kg cart flies east at 3 m/s. The other cart is 2 kg. What is its momentum, Pia?

   • −3 kg·m/s, west
   • +3 kg·m/s, east
   • −6 kg·m/s
   • 0 kg·m/s
10. 9.

    To use conservation of momentum for a two-cart collision, which system should Ren choose?

    • Just the slower cart
    • The track by itself
    • Both carts together
    • Just the faster cart
11. 10.

    Two carts collide on a rough rug. Why might their total momentum change, Tala?

    • The carts' pushes on each other change it
    • Momentum isn't conserved in collisions
    • The carts get lighter
    • The rug's friction is an outside force