Presentation on theme: "Acceleration Ch. 10.2. Objectives Describe the concept of acceleration as a change in velocity. Explain why circular motion is continuous acceleration."— Presentation transcript:
Acceleration Ch. 10.2
Objectives Describe the concept of acceleration as a change in velocity. Explain why circular motion is continuous acceleration even when the speed does not change. Calculate acceleration as the rate at which velocity changes. Graph acceleration on a velocity-time graph.
This Graph Shows Constant Velocity
This Graph Shows No Velocity
What is the distance a man can run in 1 hour if he runs at 7 mi/hr? 1.7 km 2.7 m 3.7 mi
What is the Velocity of a Plane that Travels 500 mi in 1 hour 1.500m/s mi/hr km/hr
Using the Conservation of Momentum if car has the momentum of 50 kg*m/s and a man is in the moving car the man has? 1.50 m/s 2.50 kg 3.50 kg * m/s
Acceleration Acceleration = change in velocity divided by the time interval in which the change occurred. Acceleration = a = final velocity – initial velocity time v f – v i t
Units Acceleration = V f – V i t Units = m or m s 2 s * s
Acceleration Acceleration = rate at which velocity changes over time Quick time movie acceleration Acceleration occurs when there's a change in Speed Direction Or both change
Uniform circular motion is constant acceleration. QT Centripetal Acceleration Video of bucket and water having centripetal acceleration Video of bucket and water having centripetal acceleration
Acceleration Acceleration can be determined from a graph QT Graphical Representations of Accelerations
Acceleration can also be determined from a velocity-time graph A straight line with slope = constant acceleration Slope of the line = acceleration
Horizontal line = constant speed, no acceleration or deceleration.
Examine the following graph.
A negative slope indicates that an object is slowing down or decelerating.
Calculating Acceleration Acceleration is the rate at which velocity changes. Acceleration Equation (for straight-line motion) QT Distinguishing B/W Velocity and Acceleration QT Average Acceleration SI Units = m/s 2
The Top Thrill Dragster at Cedar Point goes from 0 m/s to 53.6 m/s (120 mph) in 4 seconds. What is its acceleration? Given: a = V f = V i = t = Algebra: Substitution:
A car traveling home at a velocity of 15.6 m/s slams on its brakes and comes to a stop to avoid a dog. If it takes 5 seconds to stop, what is the cars acceleration? Given: a = V f = V i = t = Algebra: Substitution:
In what direction is the car accelerating? How can you tell mathematically?
A Porsche Boxster has an acceleration of 4.51 m/s 2. If the car starts from rest how much time would it take for the vehicle to reach a speed of 11.3 m/s? Given: a = V f = V i = t = Algebra: Substitution:
A golf ball thrown from the top of the sears tower accelerates at 9.8 m/s 2 toward the ground and lands on the pavement 9.2 seconds. If the balls final speed is 93.0 m/s what was the speed with which the ball was initial thrown? Given: a = V f = V i = t = Algebra: Substitution: