A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 one year ago
a rock dropped from a high platform is moving at 24 m/s downward when it strikes the ground. Ignore air resistance. How fast was the rock moving when it had fallen only onefourth of the distance to the ground?
8.0 m/s , 6.0 m/s, 18.0 m/s , or 12.0 m/s
? :/
anonymous
 one year ago
a rock dropped from a high platform is moving at 24 m/s downward when it strikes the ground. Ignore air resistance. How fast was the rock moving when it had fallen only onefourth of the distance to the ground? 8.0 m/s , 6.0 m/s, 18.0 m/s , or 12.0 m/s ? :/

This Question is Closed

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1please wait a moment, since I have to draw a table

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1I'm pondering....

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1we have the subsequent situation: dw:1433105987038:dw so total mechanical energy is: \[{E_{TOTAL}} = \frac{1}{2}m{v^2}\] where m is the mass of the ball or the mass of the rock

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1the mechanical energy, namely KE+PE has to be constant, during the free falling motion of our rock, and its value has to be equal to E_TOTAL

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1so we have this situation: dw:1433106277846:dw

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1at position P, we can write this equation (energy conservation): \[mg\frac{{3h}}{4} + \frac{1}{2}mv_0^2 = {E_{TOTAL}} = mgh\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok! what do we plug in?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1dividing both sides by the product m*g, we get: \[\frac{{3h}}{4} + \frac{{v_0^2}}{g} = h\]

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1then we can write: \[\begin{gathered} \frac{{v_0^2}}{g} = h  \frac{{3h}}{4} \hfill \\ \hfill \\ \frac{{v_0^2}}{g} = \frac{h}{4} \hfill \\ \hfill \\ v_0^2 = \frac{{gh}}{4} \hfill \\ \end{gathered} \]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0how can we solve for that?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1here is the next step: \[{v_0} = \sqrt {\frac{{gh}}{4}} \]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok! what do we plug in?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1no, since we have: \[h = \frac{{{{24}^2}}}{{2 \times 9.81}} = ...meters\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ohh okay so we get 29.357?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1ok! h=29.4 meters

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1now we have: \[{v_0} = \sqrt {\frac{{gh}}{4}} = \sqrt {\frac{{9.81 \times 29.4}}{4}} = ...m/\sec \]

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1yes! that's right!

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1so, what is the right option?
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.