Question

you throw a rock straight up into the air with a speed of 11.5 m/s. How long does it take the rock to reach its highest point?

Answer 1

acceleration=a=-9.8 m/s^2
Initial velocity= 11/5 m/s
Final velocity is 0 at the rock's highest point
Use the equation Final Velocity= Initial Velocity + Acceleration x Time
Substitute values: 0= 11.5+-9.8t
t= -11.5/-9.8
t= 1.1735s

Answer 2

The acceleration of gravity is 9.8m/s² downward.

That means that if no other vertical forces but gravity act on an object,
then the object's downward speed increases by 9.8m/s every second,
or its upward speed decreases by the same amount every second.

So if a rock starts out moving in the upward direction at 11.5 m/s, and the
only vertical force on it is the force of gravity, then it will lose 9.8 more m/s
of upward speed every second, and will totally run out of upward gas after

11.5 / 9.8 = 1.173 seconds .