Tuesday August 26th , 2014 By the end of the day, Scholars will be able to: Starter: Answer the following questions, and then finish the calculations for your pull back car lab from yesterday. What is the difference between speed and velocity? A man is walking down a hill. In 45 seconds he covers a distance of 57 meters. What is his speed? What is his velocity? Calculate the acceleration of an object using the equation . And answer a question like this: What is the acceleration of a car that starts at rest and increases its velocity to 60m/s east in 10 s? Agenda: Starter Acceleration Notes Acceleration Practice/Activity 8-10 minutes

Key Ideas What changes when an object accelerates? How do you calculate the acceleration of an object moving in a straight line?

1. Which of the following examples shows a change in velocity 1. Which of the following examples shows a change in velocity? Remember a change in velocity can be either a change in speed or a change in the direction of motion. Briefly explain your answers. a. a car coming to a stop at a stop sign b. a book sitting on a desk c. a yo-yo in motion d. a bicyclist making a left-hand turn at exactly 15 km/h

Acceleration and Motion What changes when an object accelerates? When an object undergoes acceleration, its velocity changes. acceleration: the rate at which velocity changes over time; an object accelerates if its speed, direction, or both change

Acceleration and Motion, continued Acceleration can be a change in speed. An increase or decrease in speed is an acceleration. Acceleration can also be a change in direction. A motorcyclist who rides around the inside of a large barrel is constantly accelerating. A person riding a Ferris wheel at an amusement park is accelerating. The acceleration that occurs in circular motion is known as centripetal acceleration.

Calculating Acceleration How do you calculate the acceleration of an object moving in a straight line? The average acceleration over a given time interval can be calculated by dividing the change in the object’s velocity by the time over which the change occurs.

Example Problem 1 The speed of a car changes from 15 m/s (about 34 mi/h) to 25 m/s (about 56 mi/hr) in 20s. Find its acceleration.

Example Problem 2 A car whose brakes can produce an acceleration of -6m/s2 is traveling at 30 m/s when its brakes are applied. (a) what is the car’s speed 2 s later? (b) What is the total time needed for the car to come to a stop?

Example Problem 3 A flowerpot falls off a second-story windowsill. The flowerpot starts from rest and hits the sidewalk 1.5 s later with a velocity of 14.7 m/s. Find the average acceleration of the flowerpot.

Top Thrill Dragster-Cedar Point Top Thrill Dragster goes from 0 to 120 mi/h in just 4 seconds. What is its acceleration in m/s2

Formula Rossa- Ferrari World Formula Rossa goes from 0 to 240 km/hr in under 5 seconds. What is its acceleration?

Real-Life Application http://www.nbclearn.com/portal/site/learn /science-of-nfl-football

Which Car Has the Greatest Acceleration? Price Information 1 Information 2 Aston Martin Vantage $147,988 0-60 mph in 5.1 s in 5 s, 0-58 mph Ferrari 360 Modena $153,500 0-60 mph in 4.6 s in 5 s, 0-66 mph Porsche 911 Turbo $116,818 0-60 mph in 3.9 s in 5 s, 0-80 mph