Published on February 12, 2008
Mass, weight and inertia: Mass, weight and inertia Mass: Mass Mass is the quantity of matter contained in an object The conventional symbol for mass is m. The common metric unit is kilogram (kg). Weight: Weight Attractive force that the earth exerts on a body Gravitational force acting on a body Direction: downward (center of earth) Magnitude: W = m g m = mass of the body g = gravitational acceleration (- 9.81 m/s/s) Weight is measured in Newtons (N). 1 kg = 9.8 N Newton 1: Law of Inertia: Newton 1: Law of Inertia Corpus omne perseverare in statuo suo quiescendi vel movendi in directum, nisi quatenus a viribus impressis cogitur statum illum mutare. Newton 1: Law of Inertia: Newton 1: Law of Inertia A body will continue in its current state of motion unless acted on by an unbalanced external force. Newton 1: Law of Inertia: Newton 1: Law of Inertia Inertia in more common usage, means a tendency of a body to resist a change in its state of motion. Inertia has no unit of measurement. The amount of inertia a body possess is directly proportional to its mass. Force, velocity and inertia: Force, velocity and inertia The amount of force needed to alter an object’s velocity is directly related to its inertia. Due to inertia a force is needed to change an objects velocity. If the resultant force = 0, velocity will remain constant same speed same direction Questions: Questions Knowing the earth is wider at the equator and flattened at the poles, where would you recommend that a shot putter compete, who wishes to set a world record? Explain? Explain why astronauts can jump great heights on the moon. What component has changed from when they left earth? Give two examples of static and dynamic inertia in sport. Attempt a vertical jump on the bathroom scales and watch the scale? What did you observe? Explain the time differences using force, mass, weight, technique and inertia.: Explain the time differences using force, mass, weight, technique and inertia.