Elastic and inelastic collisions

Answer Key - Grade 11 Science Worksheet - Building Confidence

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

1. 1.

   Using KE = ½mv², what is the kinetic energy of a 2 kg cart moving at 3 m/s, Ari?

   9 J
2. 2.

   Using KE = ½mv², what is the kinetic energy of a 4 kg cart moving at 2.5 m/s, Bo?

   12.5 J
3. 3.

   Using KE = ½mv², what is the kinetic energy of a 0.5 kg cart moving at 8 m/s, Esme?

   16 J
5. 4.

   In the charts, is momentum conserved, Jun?

   • No: cart A lost its momentum for good
   • Yes: 4 kg·m/s before and after
   • No: momentum isn't kept in collisions
6. 5.

   In the charts, is kinetic energy conserved, Kira?

   Use the picture in question 4.

   • No: collisions destroy energy
   • Yes: 8 J before and after
   • No: cart A's 8 J is gone
7. 6.

   In the charts, what kind of collision is it, Luz?

   Use the picture in question 4.

   • Elastic
   • Perfectly inelastic
   • Inelastic
8. 7.

   What makes a collision elastic, Milo?

   • Kinetic energy is conserved
   • The carts stick together
   • Momentum is lost in the collision
9. 8.

   Two carts collide with a loud clack and slow down more than in a bounce. Where did the missing kinetic energy go, Ren?

   • It was destroyed
   • It turns into extra momentum for both carts
   • Sound, heat and bending
10. 9.

    A clay ball hits a cart and sticks, leaving a dent. Where did some of the kinetic energy go, Tala?

    • Into the clay's mass
    • Nowhere; it vanished
    • Into denting and warming the clay
11. 10.

    In an inelastic collision, what happens to the total energy, Zee?

    • It stays the same, in new forms
    • It doubles after the collision
    • It gets used up