free fall physics created by k.rick. what is free fall? motion under the influence of gravitational...
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Free Fall Physics
Created by K.Rick
What is free fall?
• Motion under the influence of gravitational force only.
• When you free fall do you fall at a constant rate?
ConstantAcceleration
• Look at the data:
Use the equation above to solve for the acceleration of an object in free fall.
Time (s) Velocity (m/s)
0 0
1 10
2 20
3 30
4 40
What does the 10 m/s2 represent?
a = Δv / Δt
a = v2 – v1
t2 – t1
Is there a relationship between velocity and time because of this acceleration?
Constant Acceleration
Time (s) Velocity (m/s)
0 0
1 10
2 20
3 30
4 40
Can you write this relationship as an equation?
Is there a relationship between velocity and time because of this acceleration?
v = g t
How Fast?
• To find the instantaneous speed of an object in free fall use the following equation:
•V = g t
Check Your Understanding :
• What would be the speedometer reading on a falling rock 4.5 seconds after it drops from rest?
• How about 8 seconds?
How far?
Time (s) Distance (m)
0 0
1 5
2 20
3 45
4 80
5 125
• Can you find the mathematical relationship between time and distance? (hint: don’t forget “g”!)d = ½ g (t2)Find the distance an object will fall after 8 seconds of free fall.
How long?
• Rearrange the distance equation to solve for the time the object falls?T = 2 d / g
How long has this skydiver free fallen if he falls for 80 meters?
d = ½ g (t2)
Check Yourself :
• An object is dropped from rest and falls freely. After 6 seconds, calculate its instantaneous speed and distance fallen.Instan. Speed
V = g t
V= 10 m/s2 * 6s
V = 60 m/s
Distance
d = ½ g t2
d = ½ 10m/s2 * 6s2
d = 180 m
Double Check Yourself :
• An object is dropped from rest and falls freely. After 8 seconds, calculate its instantaneous speed and distance fallen. Distance
d = ½ g t2
d = ½ 10m/s2 * 8s2
d = 320 m
Instan. Speed
V = g t
V= 10 m/s2 * 8s
V = 80 m/s
More Practice
• An object falls a distance of 125m. What is its instantaneous speed just before it hits the ground?
(hint: find t then find v)
FYI: DaVinci’s Parachute
• This is DaVinci’s 1493 parachute design
• This is the modern reproduction of his sketch.
His design is highly functional!