Abaseball is hit at ground level. the ball is observed to reach its maximum height above ground level 3.0 s after being hit. and 2.5 s after reaching this maximum height, the ball is observed to barely clear a fence that is 97.5 m from where it was hit. how high is the fence?

y= 13.475 m

Explanation:

 Kinematics of the ball : The ball describes a parabolic trajectory.

Because ball move with uniformly accelerated movement in y we apply the following formulas:

 Formula (1)

 Formula (2)

Where:  

y :  vertical position for any time t  (m)  

y₀ : Initial vertical position   (m)

t :    time in seconds (s)

     : Initial speed in y (m/s)  

     : Final speed in y (m/s)

g: acceleration due to gravity (m/s)²

Problem development

We apply formula 1 when the ball reaches its maximum height to obtain the initial velocity at y,  :

at maximum height : t= 3 s,    = 0

We calculate the requested height using formula 2

t= 3s+2.5s = 5.5 s, , y₀ = 0

y=13.475 m

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.