Find the instantanous velocity

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To find the instantaneous velocity at t=1, the equation v(1) = [h(1+Δt) - h(1)]/Δt is used, with h(t) defined as h(t) = 16 + 24t - 16t². The calculated value of v(1) is -8 ft/sec, but there is confusion regarding the manipulation of h(1+Δt). It is clarified that h(1+Δt) should include the quadratic term, leading to the correct expression. The discussion highlights the importance of correctly applying the limits as Δt approaches 0 to confirm the final answer.
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1. Homework Statement

Find the instantaneous velocity at t=1 by computing v(1)= [h(1+LaTeX Code: \\Delta t)-h(1)]/LaTeX Code: \\Delta t

I found that v(1)= -8ft/sec. Also I know h(1)=24 but i don't understand how to manipulate the h(1+LaTeX Code: \\Delta t) to get the solution.


2. Homework Equations

h(t)=16+24t-16t2


3. The Attempt at a Solution

The solution the teacher gave is v(1)=-8-16tLaTeX Code: \\Delta
 
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Write out \frac{h(1+\Delta t)-h(1)}{\Delta t}. The part you have a problem with is probably the h(1+\Delta t) term I will give you a hint. h(1+\Delta t)=16+24(1+\Delta t)+... fill in the rest and work out the brackets.

Note that for an instant of time \Delta t \rightarrow 0 so your final answer is correct.
 
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How did you get that h(1+t)=16+24(1+t)?

and when i fill in the rest i get 16+24(1+t)-24 which when worked out would be 16+24t and is not right

:confused:
 
Don't overlook the dots. h(1+\Delta t)=16+24(1+\Delta t)+... my intention was for you to fill in the dots, so basically add the quadratic term to it as well. I hope this is sufficiently clear if not just ask again!

Edit: I just noticed that the same question was asked in the correct introductory physics section. Perhaps a mod could merge this thread with https://www.physicsforums.com/showthread.php?t=305889.
 
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