Kinetic Energy Calculator
Calculate kinetic energy from mass and velocity with step-by-step explanations.
Kinetic Energy Formula
KE = ½mv²
where: m = mass (kg), v = velocity (m/s), KE = energy (joules)
Step-by-step: 1) Square velocity. 2) Multiply by mass. 3) Divide by 2.
Kinetic Energy Examples
| Object | Mass | Velocity | KE (approx) |
|---|---|---|---|
| Baseball | 0.145 kg | 40 m/s | 116 J |
| Person running | 70 kg | 5 m/s | 875 J |
| Car on highway | 1500 kg | 25 m/s | 469 kJ |
| Bullet | 0.01 kg | 400 m/s | 800 J |
Frequently Asked Questions
What is kinetic energy?
Energy of motion. Any moving object has kinetic energy. KE = ½mv², where m = mass (kg), v = velocity (m/s). Measured in joules (J).
How does velocity affect kinetic energy?
Kinetic energy depends on velocity squared (v²). Doubling velocity quadruples kinetic energy (2² = 4). Velocity has more impact than mass.
Why is kinetic energy proportional to v²?
Energy is work needed to accelerate object from rest. Work = F·d, and d increases with v²/2a by kinematics. Results in KE ∝ v².
How does mass affect kinetic energy?
KE is directly proportional to mass. Doubling mass doubles KE (at same velocity). But this effect is weaker than velocity effect.
Is kinetic energy always positive?
Yes. KE = ½mv² is always positive (mass and v² are positive). An object moving at any speed has positive kinetic energy.
What is the relationship between KE and work?
Work done on object = change in kinetic energy. W = ΔKE. Positive work increases KE. Negative work (friction) decreases KE.
How does kinetic energy differ from potential energy?
Kinetic: energy of motion (depends on velocity). Potential: energy of position (depends on height or spring compression). Both are mechanical energy.
Can kinetic energy be converted to other forms?
Yes. Friction converts KE to heat. Braking converts KE to heat/sound. Collision can convert KE to deformation. Total mechanical energy conserved.
What are practical examples of kinetic energy?
Moving car (depends on mass and speed—safety concern). Baseball pitch (why faster pitches are harder to catch). Wind turbines (converting wind KE to electricity).
How is kinetic energy used in engineering?
Impact energy calculations (vehicle crashes). Turbine design (extracting energy from flowing water/wind). Projectile motion analysis. Energy efficiency studies.
What units are used for kinetic energy?
SI unit: joule (J) = kg·m²/s². Also: erg, calorie, electron-volt, foot-pound. Always convert to joules for consistency.
How do I solve kinetic energy problems?
Identify m (kg) and v (m/s). Apply KE = ½mv². Be careful with units. For velocity changes, use KE_f - KE_i = work done.