《物理学基捶(哈里德)学习指导10Rotation.pdf

Chapter 10 Rotation Sometimes things move, but sometimes things rotate (and talented objects can do both at the same time). Everything weve done so far also applies for rotation, using the same equations, but with different variables. fr+ 0 (Greek theta ) angular displacement a+ u (Greek ttomegatt ) angular velocity a a (Greek alpha ) angular acceleration rTL I angular mass rrrorrrent of inertia ttau - F- r (Greek ) angular force - torque P- L angular momentum Every equation weve had will also have an angular equivalent. For example, force equals ma,ss times acceleration (F: rna), so angular force equals angular mass times angular acceleration (, - Io). An object can have a velocity, which is the change in its position. It can have an acceleration, which is how fast the velocity is changing. It can have an acceleration even if the velocity is zero: throw something (other than this book) straight up, and at the instant that it is at its peak height the velocity is zero but changing, so that there is an acceleration. Weve done all this before. Its all true for rotation as well. An object can have an angular velocity, which is the change in its angular position or angular displacement, or how fast it is spinning. It can have an angular acceleration, which is how fast the angular velocity is changing is the rotation speeding up or slowing down? It can have an - is zero. a ramp, angular acceleration even if the angular velocity Roll a basketball or other round object up