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Food Is ChemicalEnergy You transformenergy every time youeat and digest food. Thefood you eat containschemical energy. Thisenergy changes intoforms that keep yourbody warm and moveyour muscles. Theamount of chemicalenergy contained in foodis measured in Calories.Check some food labelsto see how many Caloriesyour food contains.Kinetic EnergyOne soccer ball is sitting on the ground and another isrolling toward the net. How does the energy of the moving ballcompare to the one at rest? A moving ball certainly has the abilityto cause change. For example, a moving bowling ball shownin Figure 4 causes the bowling pins to fall. A moving ball hasenergy due to its motion. The energy an object has due to itsmotion is called kinetic (kih NE tihk) energy. A football thrownby a quarterback has kinetic energy. A sky diver or a leaf fallingtoward Earth also has kinetic energy.Mass, Speed, and Kinetic Energy Although movingobjects have kinetic energy, not all moving objects have the sameamount of kinetic energy. What determines the amount ofkinetic energy in a moving object? The amount of kinetic energyan object has depends on the mass and speed of the object, asshown in Figure 5. Imagine a small rock and a large boulder rollingdown a hillside at the same speed. Which would have more kineticenergy? Think about the damage the rock and the boulder could doif they hit something at the bottom of the hill. The large bouldercould cause more damage, so it has more kinetic energy. Eventhough the rock and the boulder were moving at the same speed,the boulder had more kinetic energy than the rock because it hadmore mass.Kinetic energy also depends on speed. The faster a bowlingball moves, the more pins it can knock down. When more pinsare knocked down, a greater change has occured. So the fasterthe bowling ball moves, the more kinetic energy it has. Kineticenergy increases as speed increases.Figure 4 Any moving objecthas energy because it can causechange.Identify a change that the bowlingball is causing.164 CHAPTER 6 EnergyAlan Thornton/Stone/Getty Images