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Why Speeding Kills
📖 Why Speeding Kills
Here's a fact that should terrify every driver: if you double your speed, you don't just double your kinetic energy — you QUADRUPLE it! A car at 60 mph has FOUR TIMES the kinetic energy of the same car at 30 mph. In a crash, that energy has to go somewhere — into crumpling metal, shattering glass, and injuring people. Your brakes don't just have to work twice as hard at double speed; they have to work FOUR times as hard. This isn't opinion — it's physics. The v² in the kinetic energy equation is why speed limits exist and why speeding is the single biggest factor in road deaths.
Kinetic Energy Equation (ON FORMULA SHEET ✓)
Ek = ½mv²
Kinetic Energy (J) = ½ × mass (kg) × velocity² (m/s)²
Deep Dive: Why Is Velocity SQUARED?
This is the most important thing to understand about kinetic energy. It's not just a formula to memorize — there's real physics behind it.
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🧠 Memory Aid: The KE Equation
Remember E_k = ½mv² with this sequence: "Half My Velocity Squared"
Half = the ½ | My = m (mass) | Velocity = v | Squared = the ² superscript
For the v² effect, think of road safety: "Double the speed, four times the danger." This locks in the squared relationship without even needing the formula.
Now try it yourself
Quiz · Question 1 of 15
Which of the following objects has kinetic energy stored in its kinetic energy store?
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This topic in real past papers
Every real exam question we've found on kinetic energy, with a full worked answer.