Conservation of momentum in collisions

Answer Key - Grade 11 Science Worksheet - Challenge Me

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

1. 1.

   East is positive. Two carts at rest are pushed apart by a spring. The 2 kg cart moves at 3 m/s. What is the 4 kg cart's velocity, Ari?

   -1.5 m/s
2. 2.

   East is positive. Two carts at rest are pushed apart by a spring. The 1 kg cart moves at 6 m/s. What is the 3 kg cart's velocity, Bo?

   -2 m/s
3. 3.

   East is positive. Two carts at rest are pushed apart by a spring. The 5 kg cart moves at 1.2 m/s. What is the 2 kg cart's velocity, Esme?

   -3 m/s

4. Read this first

   Cart collision trials (example data)

   trial	total momentum before (kg·m/s)	total momentum after (kg·m/s)	track
   1	6	6	smooth
   2	4	4	smooth
   3	6	4.5	rough rug

5. 4.

   In the collision trials table, which trial did not conserve momentum, Jun?

   • Each of the three did
   • Trial 3
   • Trial 1
   • Trial 2
6. 5.

   In the collision trials table, why did trial 3 lose momentum, Kira?

   • Momentum isn't conserved in collisions
   • The carts' pushes on each other used it up
   • The carts stuck together
   • Rug friction was an outside force
7. 6.

   In the collision trials table, how much momentum did trial 3 lose, Luz?

   • 1.5 kg·m/s
   • 4.5 kg·m/s
   • 10.5 kg·m/s
   • 6 kg·m/s
8. 7.

   Milo says momentum is lost when two carts stick together. Agree or disagree?

   • Agree: sticking destroys momentum
   • Agree: each cart keeps its speed instead
   • Disagree: the total momentum stays the same
   • Agree: directions don't count
9. 8.

   Noah says the total speed of two colliding carts stays the same. Agree or disagree?

   • Agree: speeds are what is conserved
   • Agree: west speeds count as positive
   • Agree: sticking is the one exception
   • Disagree: total momentum stays the same
10. 9.

    Pia says a 2 kg cart at 3 m/s east and a 3 kg cart at 2 m/s west have a total momentum of 0. Agree or disagree?

    • Disagree: the total is 12
    • Agree: 6 + (−6) = 0
    • Disagree: the faster cart wins
    • Disagree: sticking would change it
11. 10.

    A 3 kg cart at 4 m/s hits a 1.5 kg cart at rest. The 3 kg cart slows to 1 m/s. What is the 1.5 kg cart's speed after, Ren?

    • 8 m/s
    • 4 m/s
    • 2 m/s
    • 6 m/s