Get out your spirals! And write the critical questions! (right side) What is the difference between positive and negative acceleration? Turn in your TYPED Lab-Write Ups into the appropriate tray. 10 points off for every day it is late.

Acceleration

Acceleration Acceleration

The rate at which velocity changes Acceleration Acceleration The rate at which velocity changes

Remember Velocity

Remember Velocity The speed and direction an object is moving

Acceleration Acceleration For a change in velocity, how many velocities do you need? 2

Acceleration v1 v2 An original velocity and a final velocity

Acceleration Acceleration To calculate the change in acceleration you would subtract the velocities v2 – v1

Acceleration Acceleration Formula ?

Formula # 1 Acceleration Acceleration v2 – v1 a = t

Acceleration Acceleration D = Greek letter “DELTA”

Acceleration D = D v = D v = v2 – v1 DELTA = difference Difference in velocity D v = v2 – v1

Acceleration Acceleration v2 – v1 a = t

Acceleration Acceleration D v a = t D v = Difference in velocity

Acceleration Acceleration UNITS ?

Acceleration Acceleration m/sec2 miles/hr2 km/hr2

Acceleration Acceleration

Formula # 2 Acceleration Acceleration 2d a = t 2

Acceleration Acceleration Increasing speed,

Acceleration Acceleration Increasing speed, decreasing speed

Deceleration Increasing speed, decreasing speed Acceleration Deceleration Increasing speed, decreasing speed (Negative Acceleration)

Acceleration Increasing speed, decreasing speed or changing direction

Acceleration

Acceleration Examples:

Acceleration Examples: Increasing speed -

Acceleration Examples: Increasing speed - Car moves forward

Acceleration Examples: Increasing speed - Bat hitting a baseball

Acceleration Examples: Increasing speed - Track star running

Acceleration Examples: Increasing speed - Shot from a canon

Acceleration Examples: Increasing speed - Arrow from a bow

Acceleration Examples: Increasing speed - Jet taking off

Acceleration Examples: Decreasing speed -

Examples: Decreasing speed - Opposite of all our Acceleration Examples: Decreasing speed - Opposite of all our Increasing acceleration Examples. (car coming to a stop)

Acceleration

Graphing Acceleration

Acceleration

Acceleration velocity

Acceleration A plane takes off in 20 seconds at 80 m/s. What is the planes acceleration? v2 – v1 a = t End – 80 m/s Start – 0 m/s Change in velocity – 80 m/s Time interval – 20 seconds Acceleration – 4 m/s2 Velocity (end) Velocity (start) Velocity end – Velocity start ___________________________ Time interval Average Acceleration _____________________________________

Acceleration A bike going 3 m/s comes to a stop in 2 seconds. What was the bikes acceleration? v2 – v1 a = t End – 0m/s Start – 3 m/s Change in velocity – -3 m/s Time interval – 2 seconds Acceleration – (-1.5) m/s2 Velocity (end) Velocity (start) Velocity end – Velocity start ___________________________ Time interval Average Acceleration _____________________________________

Acceleration practice Example: An airplane on the runway clocked at a speed of 8 miles/hour heading East. By the time it takes off from the runway 20 seconds later, it is traveling at 260 miles/hour to the East. What is the plane’s average acceleration? Velocity (end) Velocity (start) Velocity end – Velocity start ___________________________ Time interval Average Acceleration _____________________________________ v2 – v1 a = t Velocity (end) 260 miles/hour Velocity (start) 8 miles/hour Velocity end – Velocity start 260 – 8 = 252 miles/hour Time interval 20 seconds Average Acceleration 252 miles/hour ÷20 seconds = 12.6 miles/hour/second