Question

If a ball is thrown vertically upward from the ground with an initial velocity of 56 feet per second, for how long will the ball be going upward?

Answer 1

The answer is: `1,73s`.

First of all: `v=56(feet)/s~=17m/s`.

This is an uniformed accelerated motion with

`a=-g=-9.8m/s^2`, and the law is:

`v=v_0+atrArrv=v_0-g trArrt=(v_0-v)g`.

Since `v_0=17m/s` and `v=0m/s` (in the higher point his speed is 0),

`t=(17m/s)/(9.8m/s^2)=1,73s`.