1. PHYSICS 50: Lecture 10.1 RICHARD CRAIG

2. Homework #10 Chapter 10 We will skip 10.7 Chapter 11 Sections 1,2,3 only Exercises and Problems 10.1, 10.16, 10.41, 11.12, 11.14, 11.56 Due Tuesday April 14

3. Plan for the Day Some thoughts on Quiz of last Thursday HW Questions Torque Simple torque problem Rolling Harder torque problem Quiz (again!!!)

4. Moment of inertia for common shapes

5. Torque A force applied at a right angle to a lever will generate a torque. The distance from the pivot to the point of force application will be linearly proportional to the torque produced.

6. Formal Definitions Torque Equation of Motion (like F=ma)

7. The four forces shown all have the same magnitude: F 1 = F 2 = F 3 = F 4. Which force produces the greatest torque about the point O (marked by the blue dot)? A. F 1 B. F 2 C. F 3 D. F 4 E. not enough information given to decide Q10.1 F1F1 F2F2 F3F3 F4F4 O

8. Easy Torque Problem: the unwinding cable Method #1: Energy Calculate the speed of the Block when it hits the water Method #2: Forces and Torques Calculate the tension in the cable

9. Rolling without slipping Key results: v = 0 at surface, v cm =  R

10. The race of objects with different moments

11. A. m 2 g = T 2 = T 1 B. m 2 g > T 2 = T 1 C. m 2 g > T 2 > T 1 D. m 2 g = T 2 > T 1 E. none of the above Q10.5 A glider of mass m 1 on a frictionless horizontal track is connected to an object of mass m 2 by a massless string. The glider accelerates to the right, the object accelerates downward, and the string rotates the pulley. What is the relationship among T 1 (the tension in the horizontal part of the string), T 2 (the tension in the vertical part of the string), and the weight m 2 g of the object? Hard Torque Problem