Answer:
h = 23.716 m
Explanation:
Given that,
The time taken by the stone to hit the water is, t = 2.2 s
Height of the bridge above the ground, h = ?
The distance that the body will fall through the time is given by the formula
S = 1/2 gt² m
Where,
g - acceleration due to gravity
Substituting the values in the above equation
S = 1/2 x 9.8 m/s² x (2.2 s)²
= 23.716 m
Therefore, the height of the bridge from the surface of the water is h = 23.716 m
first we make a U turn and travel towards home in t = 20 s
so the distance of home from initial position is
Now after picking up the book we travel back with speed 20 m/s
so again after t = 20 s the displacement is given as
so the net displacement is given as
so it will be displaced by total displacement 200 m
Given that,
Initial velocity , Vi = 0
Final velocity , Vf = 40 m/s
Acceleration due to gravity , a = 9.81 m/s²
Distance can be calculated as,
2as = Vf² - Vi²
2 * 9.81 *s = 40² - 0²
s = 81.55 m
For half height, that is, s = 40.77m
Vf= ??
2as = Vf² - Vi²
2 * 9.81 * 40.77 = Vf² - 0²
Vf² = 800
Vf = 28.28 m/s
Therefore, speed of roller coaster when height is half of its starting point will be 28 m/s.
I dont know but i know i dont lnow if this is true but the gravity is slowly going away every 4 year i dont know i think.
