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)
