Energy changes form

Answer Key - Grade 8 Science Worksheet - Building Confidence

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

1. 1.

   Ari reads the bar chart for a coaster cart. What is the motion energy partway down?

   300 J
2. 2.

   Bo coasts a bike down a hill. Using the bar chart, what is the motion energy at the bottom?

   750 J
3. 3.

   Esme's sled slides down a snowy slope. Using the bar chart, what is the motion energy partway down?

   420 J
4. 4.

   The cart races through the lowest point of the track. Which energy store is largest there, Kira?

   • Sound energy
   • Motion energy
   • Stored energy
5. 5.

   At the end of the ride, brakes stop Luz's cart. Where does its motion energy go?

   • Into thermal energy in the brakes and air
   • It is destroyed by the brakes
   • Back into stored energy
   • Into the cart's paint
6. 6.

   Then the cart climbs a smaller second hill and slows down. Which energy change happens, Noah?

   • Stored → motion
   • Motion → nothing
   • Motion → stored
   • Thermal → motion
7. 7.

   Pia squeezes the bike brakes, and the brake pads get warm. Which energy change happens?

   • Motion → thermal
   • Stored → motion
   • Motion is destroyed
   • Thermal → motion
8. 8.

   At the top, a cart has 500 J stored. At the bottom it has 450 J motion and 50 J thermal. What happened to the total, Ren?

   • It rose to 1,000 J
   • It dropped to 450 J
   • It stayed 500 J
   • It dropped to 50 J
9. 9.

   At the top of a hill, Tala's bike has 900 J stored. At the bottom: 820 J motion and 80 J thermal. What is the total at the bottom?

   • 820 J
   • 740 J
   • 900 J
   • 980 J
10. 10.

    A ride's second hill is lower than its first. Why must it be lower, Zee?

    • Some energy became thermal energy and sound
    • Hills must get smaller to look nice
    • Energy gets used up on the first hill
    • The cart gets lighter