Physics H131: Hints for Problem Set #13

Chapter N6 Problems

• N6S.2: How is traction related to static friction? What determines the maximum acceleration before the tires start slipping? How does the situation on a level road differ from that on an incline?
• N6S.7: Use Newton's second law!
• N6S.13: You can assume that the deceleration of the car is constant in time. Compute this deceleration. How is it related to the static friction force? Why does this provide a lower limit for the static friction coefficient?
• N6R.1: Compute first the drag force (how?) Then try to answer the question about the drag coefficient. The density of air can be found on the front inside cover. What else do you need to estimate? Perform appropriate measurements on your shadow on a wall under frontal illumination.

Chapter N7 Problems

• N7B.2: Review the properties of third-law pairs.
• N7B.4: This is like the example from class. Go through it once more, but with a different mass for the string.
• N7B.8: Draw free body diagrams for each object in the problem statement and label all forces completely. Indicate any third-law pairs; use both physics considerations and your complere notation for the forces to identify such pairs.