Definition Acceleration Vector quantity magnitude value direction Rate
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Definition: Acceleration �Vector quantity: magnitude (value) & direction �Rate at which an object changes its velocity. �“How fast an object is getting faster” If the velocity of an object is changing, it is accelerating!
Definition: Acceleration �“How fast an object is getting faster” �Every second, object goes 10 m/s faster to the north �Units are: �Meters per second �m/s/s
Equation: Acceleration �
Animation: Acceleration �Physics Classroom: Acceleration Animation
Constant Acceleration �Velocity changes by a constant amount each second. �The magnitude can change. (How fast it is going) �And/or…. The direction can change. �An object with a constant velocity is not accelerating. �In this class, ALL acceleration will be constant.
Accelerating Objects Are Changing Their Velocity
Equation: Acceleration �
A car traveling at 60 mph accelerates to 90 mph in 3 seconds. What is the car’s acceleration? Acceleration = Velocity(final) - Velocity(original) time = = 90 mph - 60 mph 3 seconds 30 mph 3 seconds = 10 mph/second
Study in Acceleration �Rocket Sled
Graphing: Acceleration Position vs. Time Slope of x vs. t = velocity Velocity vs. Time Slope of v vs. t = acceleration Accel. vs. Time
Graphing: Acceleration
Change in Velocity
- Speed vs Time Graph: Constant acceleration produces a straight line (linear slope, rise/run a = v/t
Free fall �The constant acceleration of an object moving only under the force of gravity (g). �The acceleration caused by gravity is 10 m/s 2 �If there was no air, all objects would fall at the same speed �Doesn’t depend on mass �After 1 second falling at 10 m/s �After 2 seconds 20 m/s � 3 seconds 30 m/s
Falling �Air resistance will increase as it falls faster �An upward force on the object �Eventually gravity will balance with air resistance �Reaches terminal velocity - highest speed reached by a falling object.
Terminal velocity �Force of gravity is constant air resistance increases as you speed up u until the force is equal u u Equal forces, no acceleration u constant velocity terminal velocity
Balloon Racers �What will happen if I let go of the blown up balloon? �Why did that happen? �How can we measure the speed, distance or acceleration of the balloon? �A track? �Attach the balloon to something?