Find the instantanous velocity

  • Thread starter [Nicolette]
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I have already answered this question in the other thread.In summary, the conversation discusses finding the instantaneous velocity at t=1 by using the equation v(1)= [h(1+\Delta t)-h(1)]/\Delta t and manipulating the h(1+\Delta t) term. The solution given by the teacher is v(1)=-8-16t\Delta t. The conversation also addresses the importance of filling in the dots in the equation h(1+\Delta t)=16+24(1+\Delta t)+... and working out the brackets to get the correct solution.
  • #1
[Nicolette]
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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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  • #2
Write out [tex] \frac{h(1+\Delta t)-h(1)}{\Delta t}[/tex]. The part you have a problem with is probably the [itex] h(1+\Delta t)[/itex] term I will give you a hint. [itex] h(1+\Delta t)=16+24(1+\Delta t)+... [/itex] fill in the rest and work out the brackets.

Note that for an instant of time [itex]\Delta t \rightarrow 0[/itex] so your final answer is correct.
 
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  • #3
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:
 
  • #4
Don't overlook the dots. [itex]h(1+\Delta t)=16+24(1+\Delta t)+... [/itex] 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.
 

1. What is instantanous velocity?

Instantaneous velocity is the rate of change of an object's displacement with respect to time at a specific moment in time. It is the velocity at an exact point in time, as opposed to average velocity which is calculated over a period of time.

2. How is instantanous velocity calculated?

Instantaneous velocity is calculated by taking the derivative of an object's position function with respect to time. This can be found using calculus, specifically the limit definition of the derivative. Alternatively, it can be approximated by finding the slope of a tangent line on a position-time graph at a specific point.

3. What is the difference between instantanous velocity and average velocity?

The main difference between instantanous velocity and average velocity is that instantanous velocity is the velocity at a specific point in time, while average velocity is calculated over a period of time. Average velocity is also a vector quantity, taking into account both magnitude and direction, while instantaneous velocity is typically only a magnitude.

4. Why is it important to find the instantanous velocity of an object?

Instantaneous velocity is important because it gives us information about how an object is moving at a specific moment in time. This can be useful in understanding an object's motion, predicting future motion, and analyzing the forces acting on the object.

5. Can instantanous velocity be negative?

Yes, instantaneous velocity can be negative. This means that the object is moving in the negative direction, or in the opposite direction of its positive direction. For example, if an object is moving towards the negative x-axis, its instantaneous velocity would be negative.

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