Question

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Answer 1

A lead ball is dropped into a lake from a diving board 5 meters above the water. It
hits the water with a certain velocity and then sinks to the bottom with this same
constant velocity. It reaches the bottom 5.0 sec after it is dropped.
a. How deep is the lake?
b. What is the average velocity of the ball?

Answer 2

for the first part you can use the equation:
\[v _{f}^{2}=v _{i}^{2}+2a \Delta x\] to solve for the velocity before the ball hits the water.

Answer 3

Then you can use the equation:
\[x _{f}=x _{i}+v _{i}\Delta t + \frac{ 1 }{ 2 }a \Delta t ^{2}\]
to find the depth of the lake by solving for x_f

Answer 4

To find the average velocity: Find the average velocity of before the ball hits the water by finding the time it take to hit, and then take the average of the two instances of when the ball is out of the water and when the ball is in the water.

Answer 5

For the First part, Vf and Vi are the same correct?

Answer 6

no v_f is what you are trying to solve for. meaning final velocity

Answer 7

You can assume that the ball starts from rest since it is dropped

Answer 8

for acceleration do I use the constant g?

Answer 9

exactly

Answer 10

I'll have two variable in my equation wont I? My final velocity and my final position

Answer 11

You're position is given in the problem

Answer 12

You are analyzing the instance from dropping the ball until it first hits the water

Answer 13

Would the second equation look like this \[X =5+(0*5)+(9.8*5^{2})/2\]