BELLWORK 101117 NB Write IN and todays date

BELLWORK 10/11/17 NB: Write “IN” and today’s date. Answer the following in complete sentence(s): What does acceleration mean to you? Acceleration is the rate of change in velocity.

https: //www. youtube. com/watch? v=e. SLk. JEjn. FHQ

“Through” Calculating Average Acceleration The formula for calculating average acceleration is: Acceleration (a) = final velocity (vf) – initial velocity (vi) time (sec) Standard Units of acceleration: – Meters per second – m/s/s OR m/s 2

Calculating Acceleration • A jet starts at rest at the end of a runway and reaches a speed of 80 m/s in 20 s. What is its acceleration?

Calculating Acceleration • A jet starts at rest at the end of a runway and reaches a speed of 80 m/s in 20 s. What is its acceleration? • Acceleration (a) = final velocity (vf) – initial velocity (vi) time (sec) a = 80 m/s – 0 m/s 20 sec a=4 m/s/s

Calculating Acceleration • A skateboarder is moving in a straight line at a speed of 3 m/s and comes to a stop in 2 sec. What is his acceleration? Acceleration (a) = final velocity (vf) – initial velocity (vi) time (sec) a = 0 m/s - 3 m/s 2 s a=-1. 5 m/s/s

Calculating Acceleration (a) = final velocity (vf) – initial velocity (vi) time (sec) a = 16 m/s - 0 m/s 4 s a= 4 m/s/s 0 s 1 s 0 m/s 4 m/s 2 s 8 m/s 3 s 12 m/s 4 s 16 m/s

Calculating Acceleration A skydiver accelerates from 20 m/s to 40 m/s in 2 seconds. What is the skydiver’s average acceleration? Acceleration (a) = final velocity (vf) – initial velocity (vi) time (sec) a = 40 m/s - 20 m/s 2 s a= 10 m/s/s

Calculating Acceleration An airplane accelerates off the ground from 50 m/s and reaches cruising at 100 m/s. What is the airplane’s average acceleration? Acceleration (a) = final velocity (vf) – initial velocity (vi) time (sec)

Think Aloud 1. Is it acceleration if a bird changes direction while in flight? 2. What type of acceleration does the second hand on a clock demonstrate? 3. If a car gains speed as it backs up, is this negative acceleration? 1. No. It is positive acceleration because it is speeding up. 2. Yes. A change in direction is acceleration. 3. A second hand is an example of centripetal acceleration

OUT Alex is observing a car race. As the car turnsa corner, it is traveling at 80 km/hr. As the car crosses the finish line, it is traveling at 140 km/hr. Which term describes these measures? a. Speed b. Velocity c. Average speed d. Average velocity