Understanding Kinetic Energy: Mass, Speed, and Motion | Khan Academy Physics

What is Kinetic Energy?

• 💡 Kinetic energy is defined as the energy an object possesses due to its motion.
• ⚡ This energy is always measured in joules.

Factors Affecting Kinetic Energy

• 🎯 The amount of kinetic energy an object has depends on two primary factors: its mass and its speed.
• 🧠 More mass or more speed generally leads to more kinetic energy.

Kinetic Energy and Mass

• ⚖️ When the speed of an object is kept constant, its kinetic energy increases linearly with its mass.
• 📈 This means if you double the mass, you double the kinetic energy; if you halve the mass, you halve the kinetic energy.
• 📊 A graph of kinetic energy versus mass at a constant speed forms a straight line.

Kinetic Energy and Speed

• 🚀 When the mass of an object is kept constant, its kinetic energy increases with the square of its speed.
• 💥 Doubling the speed results in a fourfold increase in kinetic energy.
• 🌟 Tripling the speed results in a ninefold increase in kinetic energy.
• 📈 A graph of kinetic energy versus speed at a constant mass forms a curve, not a straight line.

Summary of Relationships

• 🔑 Kinetic energy is directly proportional to mass.
• 🔑 Kinetic energy is proportional to the square of the speed.
• ✅ The formula for kinetic energy combines these relationships: KE = 1/2 * mass * speed^2.