1. Acceleration

2. 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!

3. 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 per second
m/s/s

4. Equation: Acceleration

5. Animation: Acceleration
Physics Classroom: Acceleration Animation

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 𝑖𝑛𝑖𝑡𝑖𝑎𝑙
A 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 mph
3 seconds =
30 mph
3 seconds =
10 mph/second

10. Study in Acceleration
Rocket Sled

13. Graphing: Acceleration
Position vs. Time
Velocity vs. Time
Accel. vs. Time
Slope of x vs. t = velocity
Slope of v vs. t = acceleration

14. Graphing: Acceleration

15. Change in Velocity

16. - Speed vs Time Graph: Constant acceleration produces a straight line (linear slope, rise/run a = v/t

17. Free fall
The constant acceleration of an object moving only under the force of gravity (g).
The acceleration caused by gravity is 10 m/s2
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

18. 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.

19. Terminal velocity air resistance increases as you speed up
Force of gravity is constant
air resistance increases as you speed up
until the force is equal
Equal forces, no acceleration
constant 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?