1. In the space below, make a sketch of your roller coaster. 2. On your sketch, label different areas of acceleration. Put a next to an area of negative acceleration, a + next to an area of positive acceleration, and a 0 next to an area of zero acceleration. 3. On your sketch, identify and label any simple machines used in your roller coaster. 4. Identify and label the part of your roller coaster where there is the greatest potential energy. 5. Use your notes and book to look at Newton s Laws of Motion. How is each of Newton s Laws shown in your roller coaster? a. Newton s First Law: An object in motion will stay in motion and an object at rest will stay at rest unless acted on by another force. On your roller coaster, your car will continue moving until gravity and friction (the other forces) act on the car pulling it to a stop. The car will stay at rest until another force (the motor or your hand) acts to move the car.
b. Newton s Second Law: The acceleration of an object depends on the mass of the object and the force acting on it. Many people saw that their cars could not complete an entire trip without a push. When this happened, it was because the car was not accelerating fast enough. Some groups fixed this by making the track higher, so that the force of gravity was greater. Another way to do this could have been to add weight to the coaster car. According to Newton s Second Law, adding weight would increase acceleration of the car. c. Newton s Third Law: For every action there is an equal and opposite reaction. The action on your roller coaster is the car moving. When the car moves, the equal and opposite reaction is the roller coaster structure swaying and moving. When this happened, you saw your car lose energy and slow down. 6. Identify forces that are acting on the car. For each force that you identify: Where is it greatest? Least? Forces acting on the car: Air friction, Sliding Friction, Gravity, Force of the motor. Gravity can exert the greatest force at the highest point, and the least force at the lowest point. The motor only exerted force as the Car traveled up the inclined plane. All other forces stayed constant as the car moved along the track. 7. Calculate the speed of your roller coaster car for three different sections of track. Record your results below. Section Length of Average Time Average of Track Section (m) Trial 1 Trial 2 Trial 3 (sec) Speed (m/s) A- B 0.56 1.44 1.40 1.56 1.47 0.38 B-C 0.86 0.50 0.47 0.55 0.51 1.69 C-D 1.83 1.62 1.60 1.57 1.60 1.14
8. Calculate the average speed your roller coaster car travels as it makes one complete trip. Record your results below. Length of Track (m) Trial 1 Trial 2 Trial 3 Average Average Speed (m/s) 3.25 3.68 3.62 3.72 3.67 0.89 9. How many average miles per hour is your roller coaster car traveling as it makes one complete trip? Use the table above and what you know about conversions. (1 mile = 1,609 meters) 0.89 meters 60 seconds 60 minutes 1 mile = 3204 miles = 1.99 mph 1 second 1 minute 1 hour 1609 meters 1609 hours 10. Calculate output and input work done on the car by the motor and simple machine apparatus. Effort Force: 0.50 N Effort Distance: 2.20 m Load Force: 1.20 N Load Distance: 0.61 m Input Work= 0.50 N x 2.20 m = 1.10 N-m Output Work = 1.20 N x 0.61 m = 0.73 N-m 11. What is the efficiency of your motor and simple machine apparatus? Efficiency = Output Work = 0.73 = 0.66 = 66 % Input Work 1.10 12. What is the total work done on the roller coaster car as it completes one trip? Total Work = Load Force x Total Distance = 1.20 N x 3.25 m = 3.90 N-m
13. What is the power done on the roller coaster car as it completes one trip? Power = Work = 3.90 N-m = 1.06 Watts Time 3.67 sec 14. What would you need to know to calculate mechanical advantage of the inclined plane and motor apparatus? To calculate ideal mechanical advantage you would need to know effort distance and load distance. To calculate actual mechanical advantage, you would need to know effort force and load force. 15. Identify energy changes that take place as your roller coaster car travels along the track. Use the word bank and make a sketch if it helps. Word Bank: Potential, kinetic, stored, chemical, mechanical, electrical, friction, heat, gravity, sliding, rolling, and air. While lifting your roller coaster car up to the starting position, the car gains gravitational potential energy, or energy that is stored in the car. As gravity pulls it down the track, the gravitational potential energy is transformed into kinetic energy (the energy of movement). Some of the kinetic energy is turned into heat by sliding friction between the wheels of the car and the axle and the sliding friction between the wheels rolling on the track. Some of the kinetic energy is also transferred to heat by air friction. While the car is moving on the track some of the energy is also transferred to the structure of the roller coaster. When the track moves, the car slows down. When you turned on the motor of your roller coaster, the stored chemical potential energy becomes chemical energy.
It is transferred to electrical energy which is then turned in to mechanical energy to spin the gears. As the car is pulled up the inclined plane, it gains gravitational potential energy again to start the cycle over.