1. Work and Power 1/29/15

2. Background Information Work (scalar): A force exerted over a distance. Work (scalar): A force exerted over a distance. Unit is joule (J) Power (scalar): The rate at which work is done. Power (scalar): The rate at which work is done. Unit is watt (W)

3. Work vs. Power When lifting an object slowly and quickly to the same height When lifting an object slowly and quickly to the same height Both have the same amount of work done Both have the same amount of work done Done slowly has less power Done slowly has less power Done quickly has more power Done quickly has more power

4. Review, Work and Power Equations Weight vs. Mass / Net Force Weight vs. Mass / Net Force Work Work Power Power

5. Work and Power Lab 1/30/15

6. Review, Work and Power Equations Weight vs. Mass / Net Force Weight vs. Mass / Net Force Distance, Velocity and Acceleration Distance, Velocity and Acceleration Work Work Power Power

7. Objective: To determine how much work and power is done in physical exercises. To determine how much work and power is done in physical exercises.

8. Pre-Lab: Convert your body weight into newtons. Convert your body weight into newtons. (1 pound = 4.45 N) (1 pound = 4.45 N) EX 1: Vince Wilfork, EX 1: Vince Wilfork, NE Patriots player, weight 325 lb.

9. Pre-Lab: EX 2: House cat of 8.6 lb. EX 2: House cat of 8.6 lb.

10. Hypothesis: (Write out the question and answer in complete sentences.) Do you think physical exercises for arms and legs will produce powers on the order of what? Do you think physical exercises for arms and legs will produce powers on the order of what? (list is on the next slide) (list is on the next slide)

11. cell phone charger (2 W) cell phone charger (2 W) clock radio (7 W) clock radio (7 W) light-bulb (15 W) light-bulb (15 W) laptop computer (50 W) laptop computer (50 W) game system (100 W) game system (100 W) TV (300 W) TV (300 W) refrigerator (600 W) refrigerator (600 W) microwave oven (900 W) microwave oven (900 W) AC Unit (1500 W) AC Unit (1500 W) electric stove/oven (3000 W) electric stove/oven (3000 W) electric clothes dryer (5000 W) electric clothes dryer (5000 W)

12. Materials: Meter stick Meter stick Stopwatch Stopwatch Books or other weights Books or other weights (Return all materials to the cart up front when finished)

13. Exercise Data Table: Exercise# of Reps Distance (m) Time (s) Weight (N) Work in 1 Rep. (J) Total Work (J) Power (W)

14. Procedures: Record your own exercises! 1.Choose an exercise that involves doing work against the force of gravity. 2.Measure the distance that you exerted the force and record in a data table. 3.Now, perform several repetitions (5 or 10) of the exercise as fast as you can. Have your lab partner(s) count the repetitions and measure the total time it takes. 4.Repeat for three more exercises. Use two exercises that use arm muscles, and two exercises that use leg muscles.

15. Examples of Exercises Name of exercise – force of gravity Name of exercise – force of gravity lifting an object (arm) – object weight lifting an object (arm) – object weight raising on toes (leg) – full body weight raising on toes (leg) – full body weight arm curls (arm) – object weight arm curls (arm) – object weight knee bends (leg) – full body weight knee bends (leg) – full body weight push-ups (arm) – half body weight push-ups (arm) – half body weight vertical jump (leg) – full body weight vertical jump (leg) – full body weight etc. etc. (1 lb. = 4.45 N) Book = 3.3 lb.

16. Work and Power Lab (Day 2) 2/4/15

17. Reminder of units! All distances need to be in meters All distances need to be in meters You will need the weights in newtons for this activity. You will need the weights in newtons for this activity. Book = 3.3 lb. Book = 3.3 lb. (1 pound = 4.45 newtons) (1 pound = 4.45 newtons)

18. Calculations: - Show the work for each exercise 1.Calculate the work done in one repetition for each exercise. ( W 1 = F · d ) 2.Calculate the total work done for each exercise. ( W total = W 1 × [# of reps] ) 3.Calculate the power done for each exercise. ( P = W total / t )

19. Conclusion: (In the 3 rd person and paragraph form) What was the range of powers for the arm exercises? What was the range of powers for the arm exercises? If you could transfer this arm power to electric power, what would it be able to power? If you could transfer this arm power to electric power, what would it be able to power? What was the range of powers for the leg exercises? What was the range of powers for the leg exercises? If you could transfer this leg power to electric power, what would it be able to power? If you could transfer this leg power to electric power, what would it be able to power? Is the power output of your arm muscles more or less than you thought it would be? (Hypothesis) Is the power output of your arm muscles more or less than you thought it would be? (Hypothesis) Is the power output of your leg muscles more or less than you thought it would be? (Hypothesis) Is the power output of your leg muscles more or less than you thought it would be? (Hypothesis) What is the relationship between work and power? What is the relationship between work and power? What is the relationship between mass and weight? What is the relationship between mass and weight?

20. cell phone charger (2 W) cell phone charger (2 W) clock radio (7 W) clock radio (7 W) light-bulb (15 W) light-bulb (15 W) laptop computer (50 W) laptop computer (50 W) game system (100 W) game system (100 W) TV (300 W) TV (300 W) refrigerator (600 W) refrigerator (600 W) microwave oven (900 W) microwave oven (900 W) AC Unit (1500 W) AC Unit (1500 W) electric stove/oven (3000 W) electric stove/oven (3000 W) electric clothes dryer (5000 W) electric clothes dryer (5000 W)

21. Make-up Data Exercises (5 Reps for each exercise) Arm curls Push ups Jumping jacks Knee bends Distances Arm curl = 43 cm Push up = 19 cm Jumping jack = 1.5 cm Knee bend = 32 cm * Covert cm to m * Time for five reps Arm curls = 3.25 s Push ups = 5.13 s Jumping jacks = 6.79 s Knee bends = 4.83 s Find the force of gravity (weight) in Newtons Weight = 2.5 pounds (arm curls) Your weight (for all the other exercises and ½ you weight for push ups) (1 pound = 4.45 Newtons)

22. Grading Rubric Title (2) Objective (3) Pre-Lab (5) Hypothesis (5) Materials (2) Data (5) Conversions (5) T-Charts (12) Conclusion (16) Order (5) Total = 60