AP Physics Announcements / Calendar Wrap up note and problem examples on Monday 11/17/14 Homework Set #3: Due Thursday 11/20/14 ◦Problems from page : #37, 41, 47, 67, 73, 77, 81 and 83 Test on Chapter 4: Friday 11/21/14 ◦The 2 HW Sets ◦Lab and Activities ◦Notes / textbook

AP Physics Lab #6 11/12/14

Purpose: The purpose of this activity is to explore factors (weight, surface area, surfaces) that may affect the starting and sliding friction of an object.

Hypothesis: You should develop hypotheses on how the factors, weight, surface area, and surfaces affect friction (increase? decrease? no effect?)

Materials: Spring scale Wooden block with hooks Masses Various surfaces (bare wood, painted wood, lab bench, carpet, plastic, metal, rubberized surface, Styrofoam, cardboard and sand paper)

Data:  Collect qualitative and quantitative data that tests the hypothesis (weight, surface area, and 10 surfaces)  Measure the forces in newtons (N)  5 different mass readings  Test 2 different surface areas

Analysis and Calculations:  Calculate: The Weights  Graph: Weight vs. Friction Force (least, mean, and most on the same graph)  Calculate: The coefficient of friction for the block and 500 g mass (10 total)  Graph Visually: The different surfaces from the least coefficient of friction to the most

Conclusion : Describe what your group learned from this activity by answering the following. I suggest that you use separate paragraphs for each in the discussion section of the lab report: 1. What effect does mass/weight have on the friction of the system? 2. What effect does surface area have on the friction of the system? 3. What effect does the type of surface have on the friction of the system? 4. What does the coefficient of friction represent, and what are the two types? (What qualitative data supports / does not support this?)  Tie your conclusion back to the hypothesis, include errors and the difference between starting and sliding friction