PHYS1171 Lecture Notes - Lecture 3: 3D Systems, Projectile Motion
Document Summary
Time and position: time is used in kinematics for describing the motion of objects, generally, zero time is when object starts to move, to represent position, we use coordinate points. In 3d systems, use orthogonal axe (x, y, z) Distance and displacement: distance- the length of path taken to get from one point to another, scalar quantity, displacement- defined as a straight line between two points, vector quantity, x = xf xi. Speed and velocity: s = d/t, v = x/ t, speed is a scalar, velocity is a vector and uses displacement, thus, average velocity could be 0m/s, but average speed is 6m/s. Graphical representation: slope = rise/run = x/ t = velocity, thus, slope at any point gives instantaneous velocity, positive slope = ball going upwards, negative speed = ball going downwards, slope = rise/run = v/ t = acceleration.
