Physics Chapter 2

Sign conventions for displacement

-Displacement is positive if the motion ends in the positive direction from where it began. -Displacement is negative if the motion ends in the negative direction from where it began. -Displacement is not necessarily the total distance covered -Displacement is only the total distance between the initial and final points

Displacement with constant uniform acceleration

-Use this equation for motions with constant acceleration to relate an object's displacement, initial velocity, final velocity, and the time interval over which the motion occurs -Use this equation for motions with constant acceleration to relate an object's displacement, initial velocity, acceleration, and the time interval over which the motion occurs

Graphical representations of acceleration

Acceleration measures the rate of change in velocity. The average acceleration equals the change in velocity divided by the time required to make the change. The acceleration at any moment can be calculated from a velocity versus time graph

Equation for average acceleration

Average acceleration is the average rate at which an object's velocity changes over some time interval. This rate includes both magnitude and direction

Equation for average velocity

Average velocity is the average rate at which an object's position changes over some time interval. It includes both magnitude (speed) and direction

Final velocity after any displacement

By combining the equations we know for calculating displacement and velocity, we can obtain a single equation that relates final velocity to the initial velocity, acceleration and displacement. This equation allows us to calculate the final velocity of a uniformly accelerating object without knowledge of the time interval between the initial and final velocities

Displacement (vector)

Change in position

<--------(-4)--⬅️1---0---➡️2---(4)------->

Distance 1 and 2 are the same; displacement is not the same due to direction; behaves much like absolute value

Position

Location in space

Graphical representation of instantaneous velocity

The slope of a line tangent to the curve on a position versus time graph gives the instantaneous velocity at that time

Graphical representation of average velocity

The slope of the line connecting two points on a graph of position versus time equals the average velocity over that time interval

Equation for displacement

To find an object's displacement, or change in position, subtract the initial position of an object from its final position. The dimension for displacement is length. Possible units for displacement include meters, inches, and centimeters

Final velocity with constant uniform acceleration

Use this equation for motions with constant acceleration to relate an object's initial velocity, final velocity, acceleration, and the time interval over which the motion occurs

Velocity equation

V= 🔼X/ 🔼T

Frame of reference

a system for specifying the precise location of objects in space and time

Motion

an object's change in position over time when compared with a reference point

Average velocity

describes how fast and in which direction an object is moving. It is calculated by dividing the total displacement by the time interval during which the displacement occurred

Speed

the distance traveled by an object divided by the time interval during which the motion occurred

For motion in one dimension, velocity is negative when...

the object moves in the negative direction on that axis system

For motion in one dimension, velocity is positive when..

the object moves in the positive direction on the defined axis system

Acceleration

the rate at which velocity changes over time; an object accelerates if it changes speed, direction, or both (can be an increase and decrease in velocity)

Velocity

the speed of an object in a particular direction (how quickly we change position

Displacement equation

🔼X= X final - x initial (X2- X1)