2 Definition: Acceleration Vector quantity: magnitude (value) & directionRate 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!
3 Definition: Acceleration “How fast an object is getting faster”Every second, object goes 10 m/s faster to the northUnits are:Meters per second per secondm/s/s
6 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.
7 Accelerating Objects Are Changing Their Velocity
8 Equation: Acceleration 𝑎𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛= 𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑡𝑖𝑚𝑒 = ∆ 𝑣 ∆ 𝑡 = 𝑣 𝑓𝑖𝑛𝑎𝑙 − 𝑣 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑡 𝑓𝑖𝑛𝑎𝑙 − 𝑡 𝑖𝑛𝑖𝑡𝑖𝑎𝑙A car goes from 0 m/s to 40 m/s in 10 seconds. What is the acceleration of the car?Accel = 𝑣 𝑓𝑖𝑛𝑎𝑙 − 𝑣 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑡 𝑓𝑖𝑛𝑎𝑙 − 𝑡 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 = 𝑚 𝑠𝑒𝑐 − 0 𝑚/𝑠𝑒𝑐 𝑠𝑒𝑐 −0 𝑠𝑒𝑐 = 40 𝑚/𝑠𝑒𝑐 10 𝑠𝑒𝑐 = 4 m/s /s
9 A car traveling at 60 mph accelerates to 90 mph in 3 seconds 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 mph3 seconds=30 mph3 seconds=10 mph/second
16 - Speed vs Time Graph: Constant acceleration produces a straight line (linear slope, rise/run a = v/t
17 Free fallThe constant acceleration of an object moving only under the force of gravity (g).The acceleration caused by gravity is 10 m/s2If there was no air, all objects would fall at the same speedDoesn’t depend on massAfter 1 second falling at 10 m/sAfter 2 seconds 20 m/s3 seconds 30 m/s
18 Falling Air resistance will increase as it falls faster An upward force on the objectEventually gravity will balance with air resistanceReaches terminal velocity - highest speed reached by a falling object.
19 Terminal velocity air resistance increases as you speed up Force of gravity is constantair resistance increases as you speed upuntil the force is equalEqual forces, no accelerationconstant velocity terminal velocity
20 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?