AY Honors/Physics/Answer Key
Define the following:
Physics
A branch of science that deals with matter, energy, motion, and force.
Mass
A quantity of matter related to weight by Newton's sencond law of motion represented mathematically as F=mA
Work
A measure of energy. If we push a heavy load, then the work that we do is how hard we push the load times how far we push the load.
[math]\displaystyle{ Work=Force \times distance }[/math]
Force
An influence on an object that causes the object to move or change direction.
Power
How much energy expended per unit of time. If you can do lots of work quickly, then you are using more power.
Power=(Work done)/(time it took to do the work)
Potential energy
The energy of an object based on its relation to other objects. For example if I lift a ball above the ground by a given distance, then the ball has the potential to fall the distance that I've raised it. The potential energy of a ball can be measured by measuring how high you raise the ball against the force of gravity on the mass of the ball.
Potential energy of the ball = (Mass of ball * Accelleration of gravity (g)) * (height we rase the ball)
We write this E=mgh
g is the acceleration of gravity and is 9.8 m/sec/sec or 32 feet/sec/sec
Kinetic energy
The amount of energy that an object has based on its motion relative to other objects. Kinetic energy in it's simplest form is related to the speed of an object in relation to the observer. Kinetic energy in it's most complex form can be heat
The kinetic energy of a moving ball can be measured by knowing 2 things about the object 1) The mass of the object. (Determined using a scale.) 2) The velocity of the object (Time how long it takes to travel a given distance)
Kinetic_energy = 0.5* (Mass_of_object) * (Velocity_of_object) ^2