# physic

 .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } Speed Speed is distance travelled by an object per unit of timespeed=distance travelled / time velocity velocity is speed in a given direction; it therefore tells us two things about moving object: its speed and its direction acceleration The rate of change of velocity is called acceleration. Acceleration refers to any change of velocity, either positive or negative.acceleration= final velocity-original velocity / time Momentum Momentum an object traveling at a specific velocity has quantity called momentum. Momentum=mass x velocityp = mv EX. p = (2.0 kg)(4.0 m/s); p = 8.0 kg-m/s Newton's first law The law of inertia, states that objects in motion tend to stay in motion and that object at rest tend to stay at rest. Newton's 2 Laws Newton’s second law describes the relationship between force, mass, and acceleration. It states that the force applied on an object equals the mass of the object times its acceleration.Force= mass x acceleration (F=ma). Newton's 3 Law The third law states that for every force there is an equal and opposite force. For example, if you push on a wall, it will push back on you as hard as you are pushing on it. The blast from the back of the rockets pushes the rocket forward. Density Density is a physical property of matter that is defined as the ratio of an object's mass to its volume. Density=mass/volume Energy Energy is ability to do workkinetic energyKinetic energy is energy associated with motion. Any moving body has this type energy because it is able to do work by moving other bodies. Kinetic energy = ½(mass x velocity)2 Potential energy Potential energy is the energy stored in a body because of its position Work Work is defined as the product of the force applied to an object and the distance through which the force is applied. Work is the transfer of energy. Work has a specific definition in physics, it is equal to the force needed to move an object multiplied by the distance it moved.Work = Force x DistanceHow much work is done if a force of 20 N is used to displace an object 3 m? W = (20 N)(3 m)=60N-m. =60 Joules because 1 Joule is equal to 1 Newton-meter Joule A joule is the unit of energy equal to the work done by a force of 1 Newton acting over distance of 1 meter. One joule is the amount of energy it takes to lift an object that weighs one Newton a one meter distance. Power Power is rate at which work is done. The power of a machine is the total work done divided by the same time taken. Since work equals force times distance, the formula power is: Power = work/time The six simple machines The six simple machines are the lever, wedge, screw, inclines planes, wheel and axle, and pulley inclined plane An inclined plane is a simple machine. An inclined plane is a ramp used to reduce the effort needed to raise or lower an object over a vertical height. wedge A wedge (klin) is a moving inclined plane Lever A lever( richag) is a simple machine. A lever bar exerts a force to move a load by turning on a pivot or fulcrum Pulley Pulley is a chain or rope wrapped around a wheel A wheel and axle A wheel and axle act as a lever that rotates in a circle A screw A screw is an inclined plane wrapped around a cylinder .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } AuthorBakhrom ID51255 Card Setphysic DescriptionPhysics laws Updated2010-11-24T20:09:52Z Show Answers