VJC 2023 Kinematics_LN

9749 H2 Physics; 8867 H1 Physics Victoria Junior College Lecture Notes Topic 2:Kinematics 1 TOPIC 2 KINEMATICS CONTENT 1. Distance and Displacement 2. Speed and Velocity 3. Displacement-Time graphs 4. Acceleration 5. Velocity-Time graphs 6. Free fall in a Gravitational field w/o air resistance 7. Deriving the equations of Kinematics 8. Free fall in a Gravitational field w air resistance 9. Projectile Motion LEARNING OUTCOMES (a) define and use displacement, speed, velocity and acceleration (b) use graphical methods to represent distance, displacement, speed, velocity and acceleration use SI base units to check the homogeneity of physics equations (c) identify and use the physical quantities from the gradients of displacement -time graphs and areas under and gradients of velocity-time graphs, including cases of non -uniform acceleration (d) derive, from the definitions of velocity and acceleration, equations which represent uniformly accelerated motion in a straight line (e) solve problems using equations which represent uniformly accelerated motion in a straight line, including the motion of bodies falling in a uniform gravitational field without air resistance (f) describe qualitatively the motion of bodies falling in a uniform gravitational field with air resistance (g) describe and explain motion due to a uniform velocity in one direction and a uniform acceleration in a perpendicular direction. 0. OVERVIEW OF KINEMATICS To begin learning about classical mechanics, our initial concentration will be solely on an object's movement, disregarding any forces that may impact or alter it. This particular branch of classical mechanics is called kinematics which is the study of motion, a continuos change of position with time. In this chapter we’ll discuss how to quantify that using three key quantities: displacement, velocity and acceleration for objects moving with respect to a coordinate axis in one and two dimensions. 1. DISTANCE AND DISPLACEMENT We start with a few definitions: • Distance is the total length of the path travelled by a body regardless of direction travelled. It is a scalar quantity meaning that it only has magnitude but no direction. • Displacement: the distance travelled in a straight line in a specified direction, from some reference point. It is a vector quantity, meaning that it has both magnitude and direction.

9749 H2 Physics; 8867 H1 Physics Victoria Junior College Lecture Notes Topic 2:Kinematics 2 Example 1: From point A, a boy travels east for 100 m to point B, then travels north for 300 m to point C. He then travels a further 200 m towards the east, reaching point D. What is the total distance he travelled, and what is his final displacement from his starting position? 100 m 300 m 200 m θ A B C D displacement 1.1 Displacement along a straight-line path To define displacement, we fix need a reference starting position wh