Question

you will use the find, equation, given, answer method to solve each problem.
johnny climbed up to the top of a tree. however, johnny fell out of the tree with an acceleration of 9.8m/s2. how long will it take johnny to hit the ground if he reaches the ground at a speed of 58m/s? remember, johnny weight is 160lbs.
what are we trying to find?
what is the equation?
what are have we been given?
you type the answer to this problem in on the next page
acceleration change in distance change in mass change in time change in velocity
acceleration = change in velocity / change in time distance = speed × time speed = distance/time
time = distance / speed velocity = change in distance / change in time change in time = change in velocity / acceleration

Explanation:

Step1: Identify the unknown

We need to find the time taken for Johnny to hit the ground.

Step2: List given values

Final velocity $v = 58\ \text{m/s}$, initial velocity $u = 0\ \text{m/s}$ (starts from rest when falling), acceleration $a = 9.8\ \text{m/s}^2$.
Change in velocity $\Delta v = v - u = 58 - 0 = 58\ \text{m/s}$

Step3: Select correct equation

Use the rearranged acceleration formula:
$\Delta t = \frac{\Delta v}{a}$

Step4: Substitute values and calculate

$\Delta t = \frac{58}{9.8}$

Answer:

$\approx 5.92\ \text{seconds}$

Corresponding FIND/EQUATION/GIVEN breakdown:

What are we trying to FIND? change in time
What is the EQUATION? change in time = change in velocity / acceleration
What have we been GIVEN? acceleration = 9.8 m/s², change in velocity = 58 m/s