“Distance - Time Graphs” Pages 320-326

What are the characteristics of a d-t graph? A Distance-Time graph plots the distance traveled by an object on the y axis and the time on the x- axis The speed is the slope (steepness) of the line. The more steep a line is the faster the object is moving. Speed is scalar ( only has magnitude no direction) Increase distance is represented by a rising line. A flat line means the object is not moving.

What are the characteristics of a d-t graph? Distance-Time Graph Distance Speed Change over time Y-axis = Distance How far away the object is from the reference point (0,0) Units: cm, m, km,, X-axis = Time Units: s, m, hrs Distn

What are the characteristics of a d-t graph? Each graph starts at a reference (starting) point at (0,0). As time progresses, the object may move away or towards the reference point.

What are the characteristics of a d-t graph? Slope: the average speed of an object change in y (rise) Slope = ------------------- change in x (run) Slope units = m/s. (y2-y1)/(x2-x1) Ex. 140-70 ---------- = 14 m/s 10-5

What does the slope of the line mean? Examine the slope of the line in order to interpret the speed at which it is moving. A linear slope (straight line) means that they are moving at a constant speed. Steeper lines mean the object is moving faster. Less steep lines mean the object is moving slower. Horizontal lines mean the object is not moving.

What is taking place between 4-6 hours? Is she moving at a faster rate from 6-8 hrs OR 8-10 hrs?

Review D-T Graph Concepts What does the y-axis display? What does the x axis display? What is the slope How do we calculate the slope? What is the reference point?

Acceleration The rate at which velocity changes Velocity is a vector: it has speed and direction. Two objects can have the same speed but different velocities because they are going in opposite directions Has magnitude (length of acceleration ex. 10m/s/s Has direction (direction of acceleration North) Acceleration = 10m/s2 N https://www.youtube.com/watch?v=9G1dhkRJ3ak

Acceleration occurs when velocity changes It is the rate of change in velocity The difference in velocity between when the object starts moving and when it ends its movement. It is Velocity ÷ Time It is measured in meters per second per second or meters per second squared (m/s2) or

Producing acceleration requires force In order to produce an acceleration, a force must be applied to an object. The type of acceleration depends on Magnitude of Force Direction of Force Direction of motion of the object Ex. A force acting in the same direction will change the speed not direction.

Everyday Versus Physical Science Usage Everyday life Acceleration means an increase in speed Deceleration means a decrease in speed In Physics Acceleration refers to any change in speed (increase and decrease) It is a vector It can change speed, direction, or both. It can be positive (increase velocity) or negative (decrease velocity)

How is average acceleration calculated?

Centripetal acceleration Acceleration that results in circular motion Always Changing in direction but not always speed It is always experience acceleration because it is always changing direction Term coined by Sir Isaac Newton when he discovered centripetal force Comes from the Latin word centrum which means center and petere which means to rush https://youtu.be/zc96zNqgNkc