13. A catapult launches a boulder with an upward velocity of 148 ft/s. The height of the boulder (h) in feet after t seconds is given by the function h = –16t² + 148t + 30. How long does it take the boulder to reach its maximum height? What is the boulder’s maximum height? Round to the nearest hundredth, if necessary. A.) 9.25 s; 30 ft B.) 4.63 s; 640.5 ft C.) 4.63 s; 1,056.75 ft *D.) 4.63 s;

Question

13.   A catapult launches a boulder with an upward velocity of 148 ft/s. The height of the boulder (h) in feet after t seconds is given by the function h = –16t² + 148t + 30. How long does it take the boulder to reach its maximum height? What is the boulder’s maximum height? Round to the nearest hundredth, if necessary. 

A.) 9.25 s; 30 ft

B.) 4.63 s; 640.5 ft

C.) 4.63 s; 1,056.75 ft

*D.) 4.63 s; 372.25 ft

Thank You

boo · Accepted Answer

thanks Jim!!!!!

If anyone found that confusing what he means to say is that if your in connexus the answer is d.

Damon · Answer

Well, I am not sure if you are allowed to use physics. that -16 in your equation is negative gravity/2 where g = 32 ft/s^2

If you are allowed to do it that way it is easy
v = 148 - 32 t 
at top v  = 0
so at top
t = 148/32 = 4.625 seconds to top
then h = -16(4.625)^2 + 148(4.625) + 30
= -342 + 684 + 30
= 372 ft

you could also use calculus on your equation to get t at max h
at top,
 dh/dt = 0 = -32 t + 148
leading to the same old t

If you do not know calculus then you must resort to completing the square on that parabola to find the vertex
 h = –16t² + 148t + 30

t^2 - 9.25 t - 1.875 = = h/16

t^2 -9.25 t = h/16 + 1.875

t^2 - 9.25 t + 21.4 = h/16 + 23.3
(t - 4.63)^2 = (1/16)( h - 372)
lo and behold, t = 4.63 and h = 372 again

asdfg · Answer

sadly u have to find the answers urself i searched everywhere

*type first name here* · Answer

lmao @boo

Maria :) · Answer

Thank you Jim do much ;-D

Approved · Answer

Damon literately gives you the answer and Jim has the correct answer. By the way Damon your name is from Vampire Diaries loving it.

Rose Lynn · Answer

Thanks both Damon and Jim. Both had correct answer. Both should be appreciated.

--Rest In Paradise-- · Answer

@Approved I love Damon Salvatore #DelenaAllTheWay

Bella · Answer

we love both JIM and DAMON

 · Answer

41 question exam anyone?

bean bean · Answer

36 for me but its just part 1 and i have 3 parts

Dare devil 😈😈😈😈😈😈😈😈😈😈 · Answer

Thanks 👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍 jim

Makovsky · Answer

Appreciate it

Astrid · Answer

Still D 

Reaches a maximum height of 372.25 feet after 4.63 seconds.

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