Notes

32 p. : col. ill.
Table of contents: How can I run? -- How do we measure speed? -- Are four legs better than two legs? -- How can I go faster? -- Why does our ball slow down? -- Why do skis slide? -- How can I swim faster? -- Why do some boats have sails? -- Why do cars go fast? -- What makes trains go? -- Why do planes roar? -- Why does it go so fast? Summary: A simple introduction to the concepts of speed, resistance, and friction, the different measurements of speed and distance, and machines that can increase speed, such as jet engines and roller skates. Includes activities.