Jump off.After reading "air force" (p. 8), build a miniature ski-jump ramp to test the force of frictionYOU NEED: 1 cardboard tube from a roll of paper towels * scissors scissors Cutting instrument or tool consisting of a pair of opposed metal blades that meet and cut when the handles at their ends are brought together. Modern scissors are of two types: the more usual pivoted blades have a rivet or screw connection between the cutting ends * pencil * meter stick * textbooks * 20 pennies * clear tape * aluminum foil Noun 1. aluminum foil - foil made of aluminum aluminium foil, tin foil foil - a piece of thin and flexible sheet metal; "the photographic film was wrapped in foil" * fine-grain sandpaper sandpaper, abrasive originally made by gluing grains of sand to heavy paper sheets. Today sandpaper is made primarily with quartz, aluminum oxide, or silicon carbide grains, and is graded according to the size of the grains. * masking tape [ILLUSTRATION OMITTED] TO DO: 1. Cut the cardboard tube in half lengthwise length·wise adv. & adj. Of, along, or in reference to the direction of the length; longitudinally. Adj. 1. lengthwise . Keep one piece. This is your ski-jump ramp. 2. Draw a line at 4 centimeters (1.5 inches) from one end of the ramp. This will be the starting line starting line n. Sports The point or line at which a race begins. Noun 1. starting line - a line indicating the location of the start of a race or a game scratch line, scratch, start . 3. Place an 18 cm (7 in.) stack of textbooks on an uncarpeted floor or on a large, cleared table. Place one end of the ramp on the floor/table and lean the other end on the textbooks. Use a strip of masking tape to secure the ramp to the books. Be careful not to obstruct ob·struct v. To block or close a body passage so as to hinder or interrupt a flow. ob·struc  tive adj. the ramp.
[ILLUSTRATION OMITTED] 4. Place 20 pennies in a stack. Using long pieces of clear tape, secure the pennies into a tightly wrapped roll. This is your ski jumper. 5. Hold your ski jumper at the start line and let go. Measure the distance your ski jumper traveled past the end of the ramp. Record the measurement in a data table. 6. Repeat Step 5 four more times. 7. Wrap the ski jumper in a piece of lightly crumpled crum·ple v. crum·pled, crum·pling, crum·ples v.tr. 1. To crush together or press into wrinkles; rumple. 2. To cause to collapse. v.intr. 1. aluminum foil. Repeat Steps 5 and 6. 8. Remove the aluminum foil. 9. Repeat Step 7 using sandpaper. Use masking tape to secure the sandpaper to the ski jumper. For each trial, be sure the masking tape faces upward and does not touch the ramp. 10. Calculate the average distance the ski jumper traveled while wrapped in each type of material. CONCLUSIONS With which wrapping did the ski jumper travel the farthest or the least far? Why do you think that is? TAKE IT FURTHER Prop the end of the ramp using a 2.5 cm (1 in.)-thick book. Repeat the activity to observe how the results change. [ILLUSTRATION OMITTED] ANSWERS The ski jumper traveled farthest when wrapped in the smoothest surface If your tape was smoother than your crumpled foil, then the taped jumper should travel farthest. The ski jumper traveled least far when wrapped in sandpaper. That's because the rougher the surface, the more friction there is to slow the ski jumper down. |
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