Background s 1. Define work. 2. What is the unit of measurement for work? 3. What is the formula for calculating work? 4. What must occur in order for work to be done? 5. If a student places a finger on a pencil and pushes with 75 N of force straight down, but the pencil doesn t move, how much work is done? Why? 6. Work the following problems. Make sure to show your work! a. A student pushes a pencil on the table with a force of 50 N. The pencil moves 0.25 m across the table. How much work is done? b. The same student pushes the same pencil with a total of 50 N of force. The pencil moves 0.3 m. How much work is done? 7. Using the two problems from Question 6, in which situation was more work done? Explain why. 8. What is the purpose of a simple machine? 1
Part I: Plan Your Investigation 1. My Question of Inquiry: 2. The Hypothesis: 3. What is the independent variable (also known as the manipulated variable)? 4. What is the dependent variable (also known as the responding variable)? 5. Is there a control group or control variable for this investigation? Explain. 6. What materials, equipment and technology will be needed for this investigation? 7. List all safety precautions that must be taken. 8. Follow the procedures listed in the Student Guide to conduct this investigation. 2
Part II: Implement Your Investigation Collect, Record, and Organize Data Work without a Simple Machine Moving a 200 g Mass to.1 m Directly Above a Surface Force (N) Distance (m).1 m.1 m.1 m Work (J) W=F x d Average = Average =.1 m Average = Work with a Simple Machine, the Ramp Moving a 200 g Mass to.1 m Directly Above a Surface Force (N) Trial 1 Trial 2 Trial 3 Average Force Distance (m) Work (J) W=F x d.6 m.4 m.2 m 0 m 3
Part II: Implement Your Investigation Collect, Record, and Organize Data 2.0 Force (N) vs. Distance (m) for.2 Joules of Work 1.8 1.6 1.4 Force (N) 1.2 1.0 0.8 0.6 0.4 0.2 0 0.1m.2m.4m.6m.8m 1m Distance in (m) 4
Part II: Implement Your Investigation, continued Analyze Data 1. What happens to the amount of force it takes to pull a mass up a ramp when you increase the length of the ramp? 2. Why did the amount of work stay the same when the length of the ramp changed? Explain your answer. 3. When you pulled on the mass and it didn t move, explain why work was not done. 4. Predict the amount of force it would take to pull a 200 g mass up a ramp that is.5 m. 5. What was the purpose of the waxed paper? 6. If you were pulling a larger mass, would you expect your results to be different? Explain. 7. How much work would be accomplished in Joules if the 200 g mass required 2 N of force to move to a distance of.2 m above the table surface? Show your calculations. 8. Which ramp would you choose to move the mass to a height of.2 m above the table surface, the.6 m,.4 m or.2 m length? Why? 5
Reflections and Conclusions 1. Is the hypothesis supported by the data? Explain. 2. How did the results reveal a relationship between the independent and dependent variable? 3. Where could have errors been made while collecting or organizing data? 4. What do you conclude about this investigation? 5. What would you do differently if you were to conduct this experiment again? 6