Vectors and Two Dimensional Motion Outline

• Quantities can be categorized as vector or scalar quantities
• Vectors
• Two vectors are equal if they have the same magnitude and direction
• The sum of two vectors is called the resultant
• Vector addition is commutative ( A+B = B+A )
• Vectors can be multiplied or divided by a scalar, changing its length and possibly flipping its direction
• The x component of a vector is found with the formula Acosθ
• The y component of a vector is foud with the formula Asinθ
• An object’s displacement is the change in its position vector
• Average velocity is its displacement divided by change in time
• An object’s instantaneous velocity is the limit of its average velocity as the change in time goes to zero
• Average acceleration is the change in velocity over the change in time
• An object’s instantaneous acceleration is the limit of its average acceleration as the change in time goes to zero
• In projectile motion, horizontal and vertical motions are independent of each other
• When an object has no horizontal acceleration, its velocity component along the x-direction is constant
• Measurements of velocity depend on a reference frame or coordinate system
• Most of the time a stationary frame of reference relative to earth is used
• A moving frame of reference is associated with an object moving at constant velocity relative to Earth