# Problem (55): From the bottom of a $25\,$ well, a stone is thrown vertically upward with an initial velocity $30\,$

Recall that projectiles are a certain types of free-fall activity with a launch direction from $\theta=90$ along with its very own algorithms .

## Solution: (a) Allow the base of your own well be the foundation

(a) How long is the basketball outside of the better? (b) The brand new stone just before going back to the better, how many mere seconds is outside of the really?

Very first, we discover just how much length golf ball rises. Recall that high section is the place $v_f=0$ so we features\begin

## The tower’s height is $20-<\rm>$ and total time which the ball is in the air is $4\,<\rm>$

Problem (56): From the top of a $20-<\rm>$ tower, a small ball is thrown vertically upward. If $4\,<\rm>$ after throwing it hit the ground, how many seconds before striking to the surface does the ball meet the initial launching point again? (Air resistance is neglected and $g=10\,<\rm>$).

Solution: Allow source be the putting area. With the help of our understood viewpoints, you will discover the initial acceleration while the \start

Problem (57): A rock is thrown vertically upward into the air. It reaches the height of $40\,<\rm>$ from the surface at times $t_1=2\,<\rm>$ and $t_2$. Find $t_2$ and determine the greatest height reached by the rock (neglect air resistance and let $g=10\,<\rm>$).

Solution: Let the trowing point (surface of ground) be the origin. Between origin and the point with known values $h=4\,<\rm>$, $t=2\,<\rm>$ one can write down the kinematic equation $\Delta y=-\frac 12 gt^<2>+v_0\,t$ to find the initial velocity as\begin

Problem (58): A ball is launched with an initial velocity of $30\,<\rm>$ vertically upward. How long will it take to reaches $20\,<\rm>$ below the highest point for the first time? (neglect air resistance and assume $g=10\,<\rm>$).

Solution: Amongst the source (surface peak) additionally the high part ($v=0$) apply the time-independent kinematic picture below to get the best peak $H$ the spot where the golf ball is at.\start

Practice Problem (59): A rock is thrown vertically upward from a height of $60\,<\rm>$ with an initial speed of $20\,<\rm>$. Find the ratio of displacement in the third second to the displacement in the last second of the motion?