Predict Energy Changes from Speed - 4th Grade Science

1. Which has more kinetic energy: same mass at $10\text{ m/s}$ or $5\text{ m/s}$?

   The object at $10\text{ m/s}$. Higher speed means more kinetic energy for same mass.

2. Which has more kinetic energy: a ball at rest or the same ball moving at $2$ m/s?

   The ball moving at $2$ m/s. Moving objects have kinetic energy; still objects don't.

3. If a moving object slows down to $0$ m/s, what is its kinetic energy?

   $0$ J. No motion means no kinetic energy.

4. What happens to kinetic energy if an object's speed becomes $0$?

   Its kinetic energy becomes $0$. No motion means no kinetic energy by definition.

5. If an object's speed decreases to $0\text{ m/s}$, what is its kinetic energy?

   $0$ (no kinetic energy of motion). No motion means no kinetic energy.

6. Which has more kinetic energy: same mass at $6\text{ m/s}$ or $3\text{ m/s}$?

   The object at $6\text{ m/s}$. Higher speed means more kinetic energy for same mass.

7. What type of energy is the energy of motion called?

   Kinetic energy. Energy from an object's motion or movement.

8. Identify the correct claim: if two objects have the same speed, which one has more kinetic energy?

   The object with greater mass has more kinetic energy. With equal speeds, $KE$ is proportional to mass.

9. Which option best describes energy change during braking: speed decreases, kinetic energy increases or decreases?

   Kinetic energy decreases. Slowing down reduces $v^2$, thus reducing $KE$.

10. Which has more kinetic energy: a $2\text{ kg}$ object at $4\text{ m/s}$ or a $4\text{ kg}$ object at $4\text{ m/s}$?

    The $4\text{ kg}$ object at $4\text{ m/s}$. More mass means more kinetic energy at same speed.

11. Which option best completes the rule: when speed decreases, kinetic energy becomes ____.

    Smaller. Lower speed always reduces kinetic energy.

12. What happens to an object's kinetic energy when its speed decreases (mass stays the same)?

    Its kinetic energy decreases. Since $KE \propto v^2$, lower speed means less energy.

13. Identify the relationship: when speed increases, does an object have more or less energy to cause change in a collision?

    More energy (more kinetic energy). More kinetic energy means more impact force.

14. Which option has more kinetic energy: a cart moving at $6$ m/s or the same cart at $3$ m/s?

    The cart at $6$ m/s. Double the speed means more energy.

15. Which has more kinetic energy: the same car at $10$ m/s or at $20$ m/s?

    The car at $20$ m/s. Double speed means four times the energy.

16. What happens to an object's kinetic energy when its speed increases (mass stays the same)?

    Its kinetic energy increases. Since $KE \propto v^2$, higher speed means more energy.

17. Which has more kinetic energy: a $3\text{ kg}$ object at $2\text{ m/s}$ or a $3\text{ kg}$ object at $6\text{ m/s}$?

    The $3\text{ kg}$ object at $6\text{ m/s}$. Higher speed means more kinetic energy for same mass.

18. Which has more kinetic energy: the same skateboard at $4$ m/s or at $8$ m/s?

    The skateboard at $8$ m/s. Double speed means four times the energy.

19. Which option has more kinetic energy: the same ball rolling faster or rolling slower?

    The ball rolling faster. Higher speed means more kinetic energy.

20. What is the most common energy change when a moving object slows down due to friction?

    Kinetic energy changes into thermal energy (heat). Friction converts motion energy to heat through molecular collisions.

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