educational

1. Free fall
• Yosr ahmed
• Moamena Samir
• Maisoon badr

2. There is two kinds of free fall:
No air resistance
1-straight down
a =g = -9.81 m/𝑠2
dropped vi= 0 m/s
2- straight up
vf= 0 m/s (at the top)
v(leaves)= positive +
v(comes back) = negative -
-Time to top = time to come back down

3. 𝑎 =
𝑣𝑓 − 𝑣𝑖
𝑡
𝑣 =
𝑣𝑓 + 𝑣𝑖
2
𝑣 =
𝑑
𝑡
Missing variables
𝑑
𝑣𝑓
𝑡
Third equation:
𝑉𝑓
2
− 𝑉ⅈ2
= 2𝑎𝑑
Second equation:
𝑑 = 𝑉𝑖𝑡 +
1
2
𝑎𝑡2
First equation :
𝑉𝑓 = 𝑎𝑡 + 𝑣𝑖

5. A ball is dropped from rest on a cliff :
- `What is the speed of the ball 5s later ?
-what is the velocity of the ball at this time ?
- How far does it travel during this time?
- What is the displacement of the ball?
Vi= 0
Vf=?
T=5
A=-9.8
Speed= + 49 m/s
Velocity= - 49 m/s
Distance = 122.5 m/s
Displacement = -122.5 m/s

6. A stone is launched straight up into the air and returns back to
the ground 14 s later :
- What is the initial speed of the ball ?
What is the maximum height attained by it ?

7. Thanks :)