Speed skating: a high-powered machine lets racers rest their legs while they soar on skates.Engineer Jorg Kahlert zips into a padded leather bodysuit
In clothing, a bodysuit, or body, is a leotard-like garment that may or may not have snaps at the crotch. . He straps on a helmet and goggles goggles, n the protective eyewear worn by dental personnel and patients during dental procedures. goggles see periocular leukotrichia. , dons elbow and knee pads, and pulls gloves onto his hands. Seconds later, the need for serious safety equipment is clear: Rolling on only the small wheels of his in-line skates, Kahlert races around a track at more than 90 kilometers (56 miles) an hour. Kahlert doesn't rely on Supermanlike legs to reach such breathtaking speeds on skates. Rather, he hitches a ride behind the Latest in extreme sports extreme sports Sports events characterized by high speed or high risk. Such sports include aggressive inline skating, wakeboarding, street luge, skateboarding, and freestyle bicycle events (wherein tricks such as back flips are performed on a bicycle). equipment: the SkootaSkate. This wheeled machine--resembling a cross between a lawn mower mower, farm machine used for cutting grasses and other hay crops. Mowers, drawn by or attached to tractors, or self-propelled, have superseded scythes. The mower is essentially an adaptation of the much earlier reaper. The first commercial mower was patented in 1847. and a motorcycle--has a high-powered engine. Kahlert and colleagues created the machine to tow trained and daring skaters to speeds much faster than they could reach themselves. MUSCLE MIGHT Normally, to reach top speeds on skates, a person uses pure leg strength--pumping back and forth against the road. "[The skater] exerts a big force on the ground," says Steven Manly, a physicist at the University of Rochester The University of Rochester (UR) is a private, coeducational and nonsectarian research university located in Rochester, New York. The university is one of 62 elected members of the Association of American Universities. in New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of . And according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. Newton's third law of motion Noun 1. Newton's third law of motion - action and reaction are equal and opposite law of action and reaction, Newton's third law, third law of motion law of motion, Newton's law, Newton's law of motion - one of three basic laws of classical mechanics , the ground pushes back with an equal and opposite force-propelling the skater forward. With each leg pump, the skater's speed increases. But using only these forces, even top in-line skaters can't attain speeds reached with a SkootaSkate. That's because each backward stroke of the leg requires a skater to perform work, or a force that moves an object through a distance. To do the work, the skater's body converts chemical energy gained from food into mechanical energy, which moves the skater's leg muscles. But the power (see Nuts & Bolts, right), or the rate at which a person can convert that energy, is limited. POWER SOURCE To surpass the speed limits set by leg power, the Skootakate propels skaters with engine power. The engine converts gasoline's chemical energy (energy stored in chemical compounds) into mechanical energy to rotate the machine's front wheel and tow the skater. One racing model of SkootaSkate boasts a mighty 2,700 watt (unit of power) engine. Even a top skaters Top Skater is a Sega arcade game released in 1997. It was built off the Sega Model 2 hardware. The arcade game was one of the first of the era where arcade games were physically manipulated. power pales in comparison. "A trained athlete can put out about 400 W of mechanical power for fairly long periods of tune, says Chris Waltham, a physicist at the University of British Columbia Locations Vancouver The Vancouver campus is located at Point Grey, a twenty-minute drive from downtown Vancouver. It is near several beaches and has views of the North Shore mountains. The 7. in Vancouver, Canada. SKOOTA STUNTS With the added power of a SkootaSkate engine, Kahlert and other skilled skaters in Europe are strapping strap·ping adj. Having a sturdy muscular physique; robust. n. 1. Straps considered as a group. 2. Material for making straps. on safety gear to race each other on enclosed en·close also in·close tr.v. en·closed, en·clos·ing, en·clos·es 1. To surround on all sides; close in. 2. To fence in so as to prevent common use: enclosed the pasture. tracks at mind-blowing speeds. Specially trained stunt skaters are also using SkootaSkates to enhance their routines. These skaters can rocket off ramps and perform mid-air flips and spins. "The amount of time they can spend in the air depends, in part, on their speed when they leave the ramp," explains Manly. To fly sky-high, these skaters need to build an extreme vertical velocity Vertical Velocity can refer to
Nuts & Bolts Power is the rate at which energy is converted from one form to another or transferred from one object to another. Consider a high-watt lightbulb: Each second, it converts more electrical energy I to light energy and heat energy J than a bulb with a lower wattage wattage the output or consumption of an electric device expressed in watts. . It's Your Choice 1 According to--, the ground pushes back on a skater's legs with an equal and opposite force. A gravity B Newton's third law of motion C power D Newton's laws Noun 1. Newton's law - one of three basic laws of classical mechanics law of motion, Newton's law of motion law of nature, law - a generalization that describes recurring facts or events in nature; "the laws of thermodynamics" of work 2 The SkootaSkate can boost a skater's speed because A the engine does little work. B it has less power than the skater's body. C the engine has a low wattage. D its engine converts energy at a higher rate than your body can. 3 Gasoline stores A mechanical energy. B chemical energy. C power. D 400 watts. 4 To jump sky-high off a ramp, a stunt skater tries to maximize A vertical velocity. B the force on the ramp. C gravity. D friction. DID YOU KNOW? * While most of the high-powered engines on SkootaSkates run on gasoline, some models of the machine sport electric engines. The electric engines are much quieter than the fuel-powered ones. * The SkootaSkate model with the 2,700-watt engine is designed for racing. A lower-power model has an electrical engine that can produce a mere 250 W. With top speeds of approximately 24 kilometers (15 miles) per hour, this model offers skaters a slight boost in speed. CRITICAL THINKING: * Besides leg power, what other factors could limit an in-line skater's speed? What types of equipment could help a skater overcome these restrictions, allowing him or her to glide faster? CROSS-CURRICULAR CONNECTIONS: MATH: Suppose a 2,700-watt engine can propel a skater to a distance of 1,500 meters in 120 seconds. Use the equation for power to calculate the force in Newtons exerted by the engine. Hint: Power = (Force x Distance)/Time RESOURCES * "Flight of the Skootaskater," by Sally Palmer, BBC Focus BBC Focus is a British monthly magazine about science and technology published in Bristol by Origin Publishing. Edited by Paul Parsons, it covers all aspects of science and technology and is written for general readers as well as people with a knowledge of science. , January 2005. * This Web site has clear explanations of forces, work, and power. Includes student activities: www.physics.ucla.edu/ k-6connection/force.wp.htm * For activities and science project ideas related to energy, see: www.energyquest.ca.gov/projects/ ANSWERS 1. b 2. d 3. b 4. a CHECK FOR UNDERSTANDING DIRECTIONS: Fill in the blanks to complete the following sentences. 1. According to Newton's--law of motion, when a skater pushes his or her leg against the ground, the ground pushes back with an--and--force--propelling the skater forward. 2. Each backward stroke of the leg requires a skater to perform work, or a force applied through a--.To do the work, the skater's body converts--gained from food--which is used to move the skater's leg muscles. 3. The SkootaSkate's engine converts gasoline's--,or energy stored in chemical compounds, into--to rotate the SkootaSkate's front wheel. 4. --is the rate at which energy is converted from one form or another, or transferred from one. And--is a unit of power. 5. To fly sky-high, stunt skaters need to build an extreme vertical--, or speed in one direction. That helps them fight against the force of--pulling them back down toward Earth. ANSWERS 1. third, equal, opposite 2. distance; chemical energy, mechanical energy 3. chemical energy, mechanical energy 4. power, object; watts 5. velocity, gravity |
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