Overlooking something, Need Help

[timpn86]

Homework Statement

2. An Olympic diver steps off of a 10. m high diving board, plunges into the water and comes to rest beneath the surface of the water 1.7 s after entering it. a) Determine the velocity at which the diver hits the water. b) Determine the average acceleration of the diver in the water.

Homework Equations

i got to determine the final velocity at which the swimmer reaches the water that in turn will be the initial velocity at which the swimmer enters the water.

equations are attached

The Attempt at a Solution

Falling
vi = 0 m/s
vf =
a = 9.8 m/s²
t =
s = 10m

In water

Vi =
Vf = 0 m/s
a =
t = 1.7 s
s =

Homework Statement

A baseball is observed to drop downwards past a 3.0 ft long open window in 0.20 s. a) Find its velocity at the top of the window. b) Find its velocity at the bottom of the window. c) Find how high above the top of the window the object was dropped.

Homework Equations

equations attached

The Attempt at a Solution

3ft x .3048 = .9144m

From Drop
vi = 0m/s
vf =
a = 9.8m/s²
t =
s =



Top of Window
vi =
vf =
a = 9.8m/s²
t = .2s
s = .9144m


i was able to finish all 7 other problems on the page but these 2. What am i overlooking?

 

[rl.bhat]

Hi timpm,welcome to PF.
Since you have solved the rest of the problem, show some attempt of these two problems. Let me see wher you are stuck.

 

[supratim1]

for first problem, i think you are proceeding in right direction. since height 10m is given, you can find the final velocity before striking water. let it be V.

so avg. acceleration is V/1.7

 

[timpn86]

haha thanks rl.bhat... upon reviewing the problem thurther i was able to find what i missed.

 

[rwisz]

Hello, it seems like you have made some progress on both problems, but there are a few things you may have overlooked. For the first problem with the Olympic diver, you correctly identified that the initial velocity is 0 m/s and the acceleration due to gravity is 9.8 m/s^2. However, you have not calculated the final velocity at which the diver reaches the water. To do this, you can use the equation vf = vi + at, where vf is the final velocity, vi is the initial velocity, a is acceleration, and t is time. You have all the values except for vf, so you can solve for it using this equation.

For the second problem with the baseball, you correctly converted the window height from feet to meters, but you have not used this value in your calculations. To find the initial velocity at the top of the window, you can use the equation vf = vi + at, where vf is the final velocity, vi is the initial velocity, a is acceleration, and t is time. In this case, the final velocity is 0 m/s, the acceleration is 9.8 m/s^2, and the time is 0.2 seconds. You can solve for vi using this equation. Similarly, to find the velocity at the bottom of the window, you can use the same equation, but this time the initial velocity is the one you just calculated and the final velocity is what you need to find.

Lastly, to find how high above the top of the window the object was dropped, you can use the equation s = vit + 1/2at^2, where s is the displacement, vi is the initial velocity, a is acceleration, and t is time. In this case, the displacement is the height of the window, the initial velocity is what you just calculated, and the time is 0.2 seconds. You can solve for s using this equation.

I hope this helps you complete the problems successfully. Remember to always check your units and make sure they are consistent throughout your calculations. Good luck!