PHYA10H3 Lecture Notes - Lecture 1: Ellipse, Asteroid Family, Kilogram
1 May 2017
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Document Summary
In physics, knowledge is acquired by observing a phenomenon or by doing an experiment. A theory is developed to explain the above observations. Repeatable, controlled, and precise experiments are performed to test the theory. If there is a disagreement between the experiments and theory, the original theory is revised and more experiments undertaken. The second (s), metre (m), and kilogram (kg) are adopted as the standard units for measuring time, length, and mass, respectively. An object"s speed, velocity, acceleration, and momentum are used to quantify its motion. These quantities are defined as speed=(change in distance or position)/(change in time), velocity=the speed of an object and the direction it is moving, acceleration=(change in velocity)/(change in time), and momentum=(an object"s mass)x(an object"s velocity). The symbols / and x mean divide by and multiply by, respectively. Galileo galilei (1564-1642) examined objects descending to the surface of the earth.
