One and two dimensional motion
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speed
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the distance traveled per unit of time. Speed is a scalar, a quantity that is described by magnitude alone. Constant speed refers to a fixed distance per unit of time. Average speed includes the total distance and total time.
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velocity
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the displacement of an object per unit of time. Since displacement includes a direction, so does velocity. Speed with direction. Velocity is a vector a quantity that has both magnitude and direction.
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vector
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a quantity that has both magnitude and direction
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reference frame
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the position from which an event is observed
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motion map
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an image that represents the position, velocity, and acceleration of an object at one-second intervals
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scalar
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a quantity that is described by magnitude alone
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Motion and reference frame
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All motion is relative. It depends on a reference frame. An object may appear to move faster or slower depending on the reference frame.
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average velocity
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The slope of a line changes when the velocity of an object changes -> The steeper the slope, the greater the velocity. The average velocity will be different than any of the other. Any point on the line will give only an instantaneous velocity.
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change in direction
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A change in direction is represented when the line on a position-time graph changes from a positive slope to a negative. slope or from a negative slope to a positive slope. A negative slope indicates an object moving towards the origin. A positive slope indicates an object moving away from the origin.
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No motion
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horizontal line - means object is not moving -> The object’s position does not change
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Motion
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Displayed in a vector !
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speed
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s = d/t -> 50 + 30 = 80 miles, 1+1 = 2h -> 80 miles/2h = 40 mph
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velocity
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v = ∆x/t
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average velocity
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v avg = ∆x/∆t = xf − xi/tf − ti -> 100 m in 10.61 s -> xf = 100 m, xi = 0 m, tf = 10.61 s, ti = 0 s -> v avg = 100 m - 0 m / 10.61 s - 0 s = 100/10.61 = 9.43 m/s
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positive acceleration
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an increase in velocity over time
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negative acceleration
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a decrease in velocity over time
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acceleration
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the rate at which velocity changes over time
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constant
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staying the same; unchanging
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Positive acceleration
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speeds up in the positive direction. slows down in the negative direction
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Negative acceleration
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slow down down in the positive direction. speeds up in the negative direction.
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Slope
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of the line on a velocity vs. time graph represents acceleration. Positive slope = acceleration, negative slope = negative acceleration
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quadrant
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a quarter of the coordinate plane
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components
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the two parts of a vector that are perpendicular to each other
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resultant vector
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the sum of two or more vectors
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vector resolution
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the process by which the components of a vector are determined
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Properties of a vector
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A vector is a quantity that has both magnitude and direction. Examples of vectors: Displacement, velocity, acceleration. Vectors are drawn using an arrow
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projectile
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an object that is set in motion following a path in which the only force acting on it is gravity.
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inertia
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the natural tendency of objects to resist a change in motion
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projectile motion
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the curved motion that results from the combination of an object’s horizontal inertia and the force due to gravity pulling the object downward. I.e. A ball rolling of the table, A player shooting a jump shot -> Projectiles follow a parabolic path
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parabolic
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having the shape of a parabola
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vectors
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Vectors are used to describe motion in two dimensions. Vectors can be broken down into x and y components. The components of a vector are the two parts of a vector that are perpendicular to each other
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
