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The Power-Thon!!Goal: To understand the how work and power are derived by participating in a set of activities and use the data collected in these activities to calculate work and power done.Background: TermDefinitionEquation, MeaningForceAny push or pull on an objectF = m × a (remember, acceleration is a constant 9.8m/s2)NewtonUnit used to label Force1N = 1kg × 1m/s2, one Newton is the force that would give 1kg an acceleration of 1m/s2EnergyThe capacity or ability to cause change (do work)There are many equations for calculating energy. You will be given them as needed.WorkForce that causes an object to displace; measured in JoulesW = F × d, work is a measurement of the force applied over a specific distance JouleUnit used to label work1J = 1N × 1m, one Newton of force is applied to an object over a one-meter distancePowerThe amount of work done in a given time, measured in watts (W)P = W/t, if work is done in less time it will require more power!WattUnit used to label Power1W = 1J of energy per second, a 60-watt light bulb uses 60 joules of energy each second it is litSample Problems:1. Bob and Rob push a football sled a distance of 20 meters using a combined force of 1,500N. How much work did EACH player accomplish assuming they were both working equally?2. Let’s look at the question above… Bob and Rob shoved the sled 20 meters in 7 seconds. How much power was required to do this work?3. Bob pushes the sled by himself. He pushes the sled 10 meters. The hi-tech sled records the work done when it is pushed. The machine read-out shows 18,500J. How much force did Bob apply to the sled?4. Rob wants to show Bob who is boss so he pushes the sled 50m! It takes Rob a total of 40 seconds to move the sled this distance. The 5,000kg sled he has pushed accelerates at a rate of 0.08m/s2. What is the force that Bob pushes the sled? Did he “show Bob who is boss”?5. How much power was required for Rob to do his work? If Bob moved his sled in 6 seconds, which player was more powerful?Procedure:Exercise #1: PUSH-UPS!!1. Record the ‘athlete’ in your group that will be participating.2. Record their approximate weight in pounds.3. Convert their weight in pounds to their mass in kilograms (follow the directions on the table). Record in table.4. Record the rate of acceleration caused by gravity. This is ALWAYS 9.8m/s2.5. Calculate the force due to gravity by multiplying their mass in kilograms by 9.8m/s2. Record in table.6. Have your athlete get in the “up” push-up position. Measure (in meters) their height from the floor to the highest point of their shoulders while in the “up” position. Record below the table.7. Have your athlete get in the “down” push-up position. Measure (in meters) the height from the floor to the highest point of their shoulders while in the “down” position. Record below the table.8. Take the difference in the two numbers (difference between steps 6 & 7) and double it. This will be the distance covered in one rep. Record this below the table where indicated. 9. Have the athlete perform as many push-ups as possible in an agreed upon time between 10 and 30 seconds. Record both the time (in the table) and the number of push-ups (in ‘reps’ below the table).10. Multiply the difference in heights by the reps and record this in the table under the column “Distance force was applied (in meters!)”.11. Studies show that during a regular push-up, you are moving about 72% of your body’s mass. If the athlete choose to do ‘bent knee’ push-ups, multiply the force by 0.56 (56%). Otherwise, multiply the athlete’s force by 0.72 (72%) and record this under the “adjusted force” column.12. Multiply the adjusted force by the distance the force was applied and record this under the “Work” column. This is the energy expended during the exercise.13. Divide the work done by the time it took the work to get done. This is the power. Record.Exercise #2: PULL-UPS!!1. Record the ‘athlete’ in your group that will be participating.2. Record their approximate weight in pounds.3. Convert their weight in pounds to their mass in kilograms (follow the directions on the table). Record in table.4. Record the rate of acceleration caused by gravity. This is ALWAYS 9.8m/s2.5. Calculate the force due to gravity by multiplying their mass in kilograms by 9.8m/s2. Record in table.6. Have your athlete do a pull-up or two. Watch their shoulders and mark with a small piece of tape on the wall the maximum height of their shoulders. Also mark the athlete’s shoulders in the lowest position while doing a pull-up and mark with a small piece of tape.8. Measure the distance between the two pieces of tape and MULTIPLY by two, and record this under table 2 where it says ‘distance between pieces of tape x2’.9. Have the athlete perform as many pull-ups as possible in an agreed upon time between 10 and 30 seconds. Record both the time (in the table) and the number of pull-ups (in ‘reps’ below the table).10. Multiply the ‘distance between the pieces of tape x2’ by the reps and record this in the table under the column “Distance force was applied (in meters!)”.11. There is no adjusted force, so leave this blank.12. Multiply the force by the distance the force was applied and record this under the “Work” column. This is the energy expended during the exercise.13. Divide the work done by the time it took the work to get done. This is the power. Record.Exercise #3: Stair Climbs!!1. Record the ‘athlete’ in your group that will be participating.2. Record their approximate weight in pounds.3. Convert their weight in pounds to their mass in kilograms (follow the directions on the table). Record in table.4. Record the rate of acceleration caused by gravity. This is ALWAYS 9.8m/s2.5. Calculate the force due to gravity by multiplying their mass in kilograms by 9.8m/s2. Record in table.6. Measure the distance between the second flight of stairs and the third flight of stairs. Take the measuring tape and measure the distance from the second flight just below bottom step to the top of the highest step on the third flight of steps. Multiply this distance by two and record this under the table where it says ‘height of stairs’. Be sure to measure in meters!!7. Have the athlete run up and down the stairs as many times as possible in an agreed upon time between 30 and 60 seconds. Record the time in the table and the reps completed in the space below the table. When recording reps, it is expected that you estimate partial reps. So, if the athlete runs up the steps 7 times and gets to the bottom as time runs out, you should record 7.5 reps.8. Multiply the reps by the ‘height of stairs’ and record this under the “Distance force was applied (in meters!)” column.9. Multiply the “Distance force was applied (in meters!)” by the force. This should be recorded in the ‘work’ column.10. Divide the work by the time in which the work was completed and record this in the power column.Exercise #4: Wall Jumps!!1. Record the ‘athlete’ in your group that will be participating.2. Record their approximate weight in pounds.3. Convert their weight in pounds to their mass in kilograms (follow the directions on the table). Record in table.4. Record the rate of acceleration caused by gravity. This is ALWAYS 9.8m/s2.5. Calculate the force due to gravity by multiplying their mass in kilograms by 9.8m/s2. Record in table.6. Have the athlete perform a few wall jumps and watch how high and low their hips elevate and sink. Again, mark these distances on the wall with two small pieces of tape.8. Measure the distance between the two pieces of tape and record this under the table where it says distance jumped.9. Have the athlete perform a maximum number of wall jumps in an agreed upon time between 20 and 40 seconds and record the time in table 4 and the reps in the space below the table.10. Multiply the reps by the distance jumped and record this under the “Distance force was applied (in meters!)”. Notice we did NOT multiply the distance jumped by two. Remember this!11. Multiply the force by the “Distance force was applied (in meters!)” and record this under the work column.12. Divide the total work done by the time it took to do that work and record this under the power column of table 4.Exercise #5: Bicep Curls!!1. Record the ‘athlete’ in your group that will be participating.2. Choose a dumbbell and add 1.5pounds. Record this weight of the dumbbell + hand in pounds on the table.3. Convert this weight in pounds to the mass in kilograms (follow the directions on the table). Record in table.4. Record the rate of acceleration caused by gravity. This is ALWAYS 9.8m/s2.5. Calculate the force due to gravity by multiplying the mass in kilograms by 9.8m/s2. Record in table.6. Have the athlete take a piece of string and pinch it between their thumb and forefinger. Have another group member pinch the string loosely just below the athlete’s thumb. Have the athlete do a ‘mock curl’. While the athlete is doing this, the partner should hold the string parallel to the floor and let the excess string slide through their fingers. When the athlete stops curling, the partner should pinch the string. Measure the distance between the athlete’s thumb clutching the string and the partners thumb clutching the string. Multiply this number by two and record in the ‘distance for one curl’ area just under the table. It should be in METERS!7. Have the athlete perform as many curls as possible for an agreed upon time between 30-60 seconds. Record the time in the table and the number of reps below the table.8. Multiply the number of reps by the ‘distance for one curl’ and record this under the “Distance force was applied (in meters!)” column of table 5.9. Multiply the force by the “Distance force was applied (in meters!)” and record this in the work column.10. Divide the work by the amount of time that the work was done and record this in the power column.TABLE 1: Exercise #1: push-upsAthleteIn poundsIn kilograms (divide by 2.4)Acceleration due to gravity (9.8ms2)Force (multiply by)Adjusted Force (not needed here!)Distance force was applied (in meters!)Work (J)(F × d)Time Required to do workPower(W divided by time)Distance at “up” point = Distance at “down” point: Difference in heights = _____ × Reps = _____ = distanceTABLE 2: Exercise #2: pull-upsAthleteIn poundsIn kilograms (divide by 2.4)Acceleration due to gravity (9.8ms2)Force (multiply by)Adjusted Force (not needed here!)Distance force was applied (in meters!)Work (J)(F × d)Time Required to do workPower(W divided by time)Distance between pieces of tape x2 = _____ × Reps = _____ = distanceABLE 3: Exercise #3: stair climberAthleteIn poundsIn kilograms (divide by 2.4)Acceleration due to gravity (9.8ms2)Force (multiply by)Adjusted Force (not needed here!)Distance force was applied (in meters!)Work (J)(F × d)Time Required to do workPower(W divided by time)Height of Stairs = _____ × Reps = _____ = distanceTABLE 4: Exercise #4: Wall JumpsAthleteIn poundsIn kilograms (divide by 2.4)Acceleration due to gravity (9.8ms2)Force (multiply by)Adjusted Force (not needed here!)Distance force was applied (in meters!)Work (J)(F × d)Time Required to do workPower(W divided by time)Distance between pieces of tape x2 = _____ × Reps = _____ = distanceTABLE 5: Exercise #5: Bicep curlsAthleteIn poundsIn kilograms (divide by 2.4)Acceleration due to gravity (9.8ms2)Force (multiply by)Adjusted Force (not needed here!)Distance force was applied (in meters!)Work (J)(F × d)Time Required to do workPower(W divided by time)Distance of one curl = _____ × Reps = _____ = distance ................
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