CIRCULAR MOTION NOTES

MACRO H2 Physics Topic 6: Motion in a Circle Notes 2 ©MACRO Learning Physics All Rights Reserved under 9836 3500 Copyright Act (Cap. 63) of Singapore Checklist: Motion in a Circle Check (ü) 1. I am able to express angular displacement in radians and use its respective formula. 2. I am able to show an understanding of and use the concept of angular velocity to solve problems. 3. I am able to recall and use 𝑣=𝑟𝜔 to solve problems. 4. I can qualitatively describe the motion due to a constant perpendicular force. 5. I am able to recall and use 𝑎=𝑟𝜔! and 𝑎="!# to solve problems. 6. I am able to recall and use 𝐹=𝑚𝑟𝜔! and 𝐹=$"!# to solve related problems. 7. I am able to distinguish between uniform and non-uniform circular motion by a. Identifying the respective forces acting on an object in non-unform circular motion b. Resolving relevant forces in the intended directions.

MACRO H2 Physics Topic 6: Motion in a Circle Notes 3 ©MACRO Learning Physics All Rights Reserved under 9836 3500 Copyright Act (Cap. 63) of Singapore Introduction Why does water stay at the bottom of a container when it is swung in a vertical circle? Why do we feel weightless in orbit in space? Why are we slightly heavier in the north pole than on the equator? Many phenomenon in our lives can be explained through the topic of circular motion, the study of objects moving in a circular paths, and the conditions required to stay in circular motion. Angular Displacement Angular Displacement is the angle swept out by the radius r joining the body to the centre of a circle. Following the formula for arc length, the angular displacement 𝜃, is given by the ratio of the arc length s, and the radius of the circle, r. One radian is defined as the angle subtended at the centre of the circle by an arc equal in length to the radius of the circle. Conversion from radians(𝑟𝑎𝑑) to degrees: 𝐴𝑛𝑔𝑙𝑒 𝑖𝑛 𝑟𝑎𝑑 ×180°=𝐴𝑛𝑔𝑙𝑒 𝑖𝑛 °×𝜋 Standard conversion formula: Active recall: What is the definition of one joule? 𝜃=𝑠𝑟 𝐴𝑛𝑔𝑙𝑒 𝑖𝑛 𝑢𝑛𝑖𝑡 𝑥×𝑞𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑖𝑛 𝑦𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡 𝑞𝑢𝑎𝑛𝑖𝑡𝑦 𝑖𝑛 𝑢𝑛𝑖𝑡 𝑥 =𝐴𝑛𝑔𝑙𝑒 𝑖𝑛 𝑢𝑛𝑖𝑡 𝑦

MACRO H2 Physics Topic 6: Motion in a Circle Notes 4 ©MACRO Learning Physics All Rights Reserved under 9836 3500 Copyright Act