Science · Grades 9–12
Kinetic energy
Square speed before multiplying. This is the classical translational kinetic-energy model.
The key idea
Square speed before multiplying. This is the classical translational kinetic-energy model.
E_k = ½mv²
Worked examples
A 8 kg object has speed 5 m/s. Find its classical kinetic energy in J.
½ × 8 × 5² = 100
100 J
A 18 kg object has speed 14 m/s. Find its classical kinetic energy in J.
½ × 18 × 14² = 1764
1764 J
Try it yourself
A 8 kg object has speed 18 m/s. Find its classical kinetic energy in J.
A 28 kg object has speed 14 m/s. Find its classical kinetic energy in J.
Check your understanding
Answers and marking notes
- 1296 J
½ × 8 × 18² = 1296
- 2744 J
½ × 28 × 14² = 2744
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.