MOTION BY MARK AND ZYAN

Section 1vocab Frame of reference – Is a system of objects that are not moving with respect to one another. Relative motion – Is movement in relation to the frame of reference. Distance – Is the length of a path between two points. Resultant vector – The vector sum of two or more vectors. First law of motion- An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted on by a equal or greater force.

Section 1 key points To describe motion accurately and completely describe motion, a frame of reference is needed. Distance is the length of the path between two points. Displacement is the direction from the starting point and the length of a straight line from the starting point to the ending point Add displacements using vector addition. The SI unit for measuring distance is the meter. To describe an object's given position relative to given point you need to how far away and in what direction the object is from that point. Displacements are sometimes used when giving directions Displacements are an example of a vector

Section 2 vocab Speed – is the ratio of the distance an object moves to the amount of time the object moves. Average speed – The total distance traveled divided by the time it takes to travel that distance. Instantaneous speed – The rate which an object is moving at a given moment in time. Velocity – The speed and distance an object is moving. Second law of motion- Force = Mass x Acceleration

Section 2 key points Average speed is computed for the entire duration of a trip, and instantaneous speed is measured at a particular distant the slope of a line distance - time graph is speed velocity is a description of both speed and direction of motion. Velocity is a vector. Two or more vectors can be added by vector addition. Acceleration = Total distance/Total time, or d/t The SI unit of speed is meters per second(m/s) A distance-time graph is a good way to describe motion The slope of the line on a distance-time graph indicates the speed of the object

Section 3 vocab Acceleration – The rate at which velocity changes. Free fall – The movement of an object towards earth solely because of gravity. Constant acceleration – A steady change in velocity Linear graph – Displayed data will form line parts. Nonlinear graph – The data points are connected to form a curve Third law of motion- For every action, there is an equal or opposite reaction

Section 3 key points Acceleration can be described as changes in speed, changes in direction, or changes in both. Acceleration is a vector. You can calculate acceleration for straight-line motion by dividing the change in velocity by the total time The slope of a speed-time graph is acceleration instantaneous acceleration is how fast a velocity is changing at a specific instant Objects falling near Earth's surface accelerate downward at a rate of 9.8m/s^2 Acceleration = Change in velocity/Total time = (vf-vi)/time If an object is going at a constant speed its acceleration is 0 Accelerated motion is represented by a curve on a distance-time graph Acceleration is the rate at which velocity changes Sometimes motion is characterized by changes in both speed and direction at the same time

Other Vocab Words gravity - A force that acts between two masses Force - A push or pull that acts on an object Friction - A force that opposes the motion of objects that touch as they move past each other Mass - A measure of the inertia of an object that depends on the amount of matter the object contains Weight - The force of gravity acting on an object Momentum - The product of an object's mass and its and its velocity Work - The product of force and distance Projectile Motion - The motion of a falling object after it is given an initial forward velocity Law of conservation of momentum - If no net force acts on a system, then the total momentum of the system does not change

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