Dynamics
posted by DHilsath .
A ball is thrown vertically upward with a velocities of 18 m/s. Two seconds later another ball is thrown upwards with a velocity of 13.5 m/s. at what position above the ground will they meet?

The time of the first ball motion to the top point is
v=v(o1) –gt, v=0,
t=v(o1) /g=18/9.8 = 1.84 s.
The maximum height of the 1st ball is
H= v(o1) •t –gt²/2=16.53 m.
When the 2nd ball starts, the 1st ball is on its return trip during 21.84 =0.16 s.
It covers the distance hₒ=g(0.16)²/2 =0.125 m. and has the downward velocity
v(1)=g(0.16)=1.568 m/s.
At this instant the distance between two balls is 16.530.125=16.4 m, and two balls are moving towards each other: the first ball accelerates downward with initial velocity v(1)=1,568 m/s, the second ball decelerates upward at initial velocity v(2)=13.5 m/s. They cover the distances:
the1st ball h1= v1•t+gt²/2; the 2nd ball h2=v2•tgt²/2.
h1+h2= 16.4 m.
=> v1•t+gt²/2+ v2•tgt²/2 =16.4
t=16.4/(v1+v2)=16.4/(1.568+13.5)=1.088 s.
The point where the balls mett is located
h= v2•tgt²/2 =13.5•1.088g•(1.088)²/2 =8.89 m (above the ground)
Respond to this Question
Similar Questions

Physics/ Precalculus
If a ball is thrown upward from a building 30 m tall and the ball has a vertical velocity of 25 m/s, then its approximate height above the ground t seconds later is given by h(t) = 30 + 25t  5t^2 a. After how many seconds does the … 
physics
two students are on a balcony 20.6 m above the street. One student throws a ball vertically downward at 14.7 m/s. At the same instant, the other student throws a ball vertically upward at the same speed. The second ball just misses … 
physics
two students are on a balcony 20.6 m above the street. One student throws a ball vertically downward at 14.7 m/s. At the same instant, the other student throws a ball vertically upward at the same speed. The second ball just misses … 
math
A ball is thrown from the edge of a cliff with an initial velocity of 60·m/s upward. Answer the following questions using + (upward) and  (downward) to indicate the direction of the velocity. Ignore air resistance and assume the … 
Algebra
If a ball is thrown vertically upward from a height of 56ft. above ground with an initial velocity of 40ft. per second, then the height of the ball above ground t seconds after it is thrown is given by f(t)=16t^2 + 40t +56. How many … 
math
A person standing on the roof of a building throws a ball directly upward. The ball misses the rooftop on its way down and eventually strikes the ground. The function s(t) = −16t2 + 64t + 80 describes the ball’s height above … 
math
A ball is thrown vertically upward with a velocities of 18 m/s. Two seconds later another ball is thrown upwards with a velocity of 13.5 m/s. At what position above the ground will they meet? 
BTech, Mechanical
A ball is thrown vertically upward with velocities of 18 m/s. Two seconds later another ball is thrown upwards with a velocity of 13.5 m/s. At what position above the ground will they meet? 
physics
A ball is thrown vertically upward from the ground with an initial velocity of sixty four feet per second. if the positive direction is up to 't' seconds is the time the has elapse since the ball was thrown and 's' is the distance … 
dynmic
Ball A is thrown vertically upwards with a velocity of 30m/s from the ground. After 3 seconds ball B is also thrown vertically upwards with a velocity of 50m/s from the ground. Determine the time at which ball A and B will meet in …