world problem

Question

 A circus juggler throws a ball upward with an initial velocity of 15.8 m/s. How long does he have before it comes back down and he has to catch it? Assume he catches it at the same height from which he threw it and that we can neglect air friction.

Answer 1

Basic physics kinematic problem.

 

What you know is the initial velocity is 15.8 m/s.  You also know acceleration due to gravity is -9.8 m/s².  Finally when it reaches the top point the final velocity will be 0. 

 

This is at its highest point.  Remember it still has to come down.

 

 

V_f = v_i + at

 

 

0 = 15.8 + (-9.8) t

 

Now it becomes an algebra problem. 

 

-15.8 = -9.8t

 

Time to reach its highest point is 1.6122 seconds. 

 

It will take double this time to come back down so 1.6122 * 2 = 3.224 seconds.