# Shared Flashcard Set

## Details

QCP-Physics
vocabulary chapters 7, 8, & 9
21
Physics
04/07/2009

Term
 Displacement
Definition
 The change of position, the length of a staight line from the starting point (x0) to the end point(x1).
Term
 Distance
Definition
 The length of the path from the starting point to the end point.
Term
 Average Velocity
Definition
 The change in position(the displacement) traveled by a body divided by the time taken to change that position:   Vav = Change in X / Change in T   (velocity is speed/magnitude with direction)
Term
 Average Speed
Definition
 The distance traveled (along the path taken) divided by the time taken to travel that distance.   Vav = d/t
Term
 Average Acceleration
Definition
 Defined similarily to the average velocity.   Aav = change in V / change in T   (Note: if the acceleration doesn't change, the average acceleration is the accleration throughout the problem)
Term
 Magnitude
Definition
 The size of something compared to a standard. A quantity's size or amount without regard to its direction; the "length" of a vector.
Term
 Scalar Quantity
Definition
 A measurement with only magnitude.
Term
 Vector Quantity
Definition
 A measurement with magnitude and direction.
Term
 Resultant Vector
Definition
 That single vector which represents the sum of several original vectors.
Term
 Pythagorean Theorem
Definition
 The sum of the squares of the legs of a right triangle equals the square of the hypotenuse.   a^2 + b^2 = c^2
Term
 Componenets
Definition
 The parts of a vector in a particular direction, found along two perpendicular axes.
Term
 Projectile
Definition
 Any object upon which the only force is gravity. The path of it is called its trajectory. The horizontal and vertical components of a projectile's velocity are independent of each other. The horizontal velocity is always constant unless acted upon by some other horizontal force.
Term
 Normal Force is NOT equal to the force of gravity when:
Definition
 1. the surface on which the object rests is not horizontal 2. there are other vertical forces (or a component of a force is vertical)
Term
 Centripetal Acceleration
Definition
 For an object moving at a speed v in a circle of radius r, the directio of the motion must be continuously changing. That is, there is continuous acceleration. The direction of this acceleration is towards the center of the circle and has a magnitued of Ac = v^2/r
Term
 Displacement Vector
Definition
 The distance and direction between the starting and ending points of an object's motion. You can write it three ways: 1. with a vector diagram 2. as a magnitude-angle pair 3. as an x-y pair
Term
 Vertical Velocity
Definition
 Vertical velocity increaces because of the acceleration of gravity. As a result, both the magnitude(speed) and direction of the velocity vector change.   Vy = gt   This equation is only suitable for situations where the projectile starts with zero velocity.
Term
 Horizontal Distance
Definition
 The horizontal distance a projectile goes is the horizontal speed(Vx) multiplied by the time (t). The horizontal speed is always constant unless acted upon by another force. The equation is only suitable for situations where the projectile starts with zero velocity.
Term
 Vertical Distance
Definition
 The vertical distance the projectile travels can be calculated using the equation d=Vavg*t. The average velocity must be used because the vertical motion is accelerated.   Dy = 4.9t^2   This equation is only suitable for situations where the projectile starts with zero velocity.
Term
 Angular Speed
Definition
 The rate at which an object rotates or revolves.   Angular speed = rotations OR degrees / time
Term
 Linear Speed
Definition
 The distance traveled per unit of time.   Linear speed(m/s) = circumference / time   v = 2 π r /t
Term
 centripetal force
Definition
 A force that causes an object to move in a circle. It is created by a force perpendicular to the direction of motion that causes the object to change its path from a line to a circle, without changing speed. This force is always directed towards the center of the circle in which an object moves. These forces change direction so they remain pointed toward the center of the circle. Velocity is always perpendicular to the force. 1. Centripetal force is directly proportional to the mass. A 2 kg object needs twice the force to have the same circular motion as a 1 kg object. 2. Centripetal force is inversely proportional to the radius of its circle. The smaller the circle, the greater the force. An object moving in a one-half-meter circle needs twice the force it does when it moves in a one-meter circle at the same linear speed. 3. Centripetal force is directly proportional to the square of the object's linear speed. Doubling the speed requires four times the centripetal force. Tripling the speed requires nine times the centripetal force.
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