Math Problem Statement

For the position function s(t) = -16t^2 + 101t, complete the table with appropriate average velocities. Make a conjecture about the value of the instantaneous velocity at t = 3.

Solution

Let's solve the problem step by step using the given position function s(t)=16t2+101ts(t) = -16t^2 + 101t.

1. Average Velocity Formula:

The average velocity over an interval [a,b][a, b] is given by the formula: vavg=s(b)s(a)bav_{\text{avg}} = \frac{s(b) - s(a)}{b - a} where s(t)s(t) is the position function.

2. Calculate the values for each time interval:

(a) Time Interval [2,3][2, 3]:

  • s(2)=16(2)2+101(2)=64+202=138s(2) = -16(2)^2 + 101(2) = -64 + 202 = 138
  • s(3)=16(3)2+101(3)=144+303=159s(3) = -16(3)^2 + 101(3) = -144 + 303 = 159

Now, the average velocity: vavg=15913832=211=21v_{\text{avg}} = \frac{159 - 138}{3 - 2} = \frac{21}{1} = 21

(b) Time Interval [2.9,3][2.9, 3]:

  • s(2.9)=16(2.9)2+101(2.9)=16(8.41)+292.9=134.56+292.9=158.34s(2.9) = -16(2.9)^2 + 101(2.9) = -16(8.41) + 292.9 = -134.56 + 292.9 = 158.34

Now, the average velocity: vavg=159158.3432.9=0.660.1=6.6v_{\text{avg}} = \frac{159 - 158.34}{3 - 2.9} = \frac{0.66}{0.1} = 6.6

(c) Time Interval [2.99,3][2.99, 3]:

  • s(2.99)=16(2.99)2+101(2.99)=16(8.9401)+302.99=143.0416+302.99=159.9484s(2.99) = -16(2.99)^2 + 101(2.99) = -16(8.9401) + 302.99 = -143.0416 + 302.99 = 159.9484

Now, the average velocity: vavg=159159.948432.99=0.05160.01=5.16v_{\text{avg}} = \frac{159 - 159.9484}{3 - 2.99} = \frac{0.0516}{0.01} = 5.16

(d) Time Interval [2.999,3][2.999, 3]:

  • s(2.999)=16(2.999)2+101(2.999)=16(8.994001)+302.999=143.904016+302.999=159.094984s(2.999) = -16(2.999)^2 + 101(2.999) = -16(8.994001) + 302.999 = -143.904016 + 302.999 = 159.094984

Now, the average velocity: vavg=159159.09498432.999=0.0050160.001=5.016v_{\text{avg}} = \frac{159 - 159.094984}{3 - 2.999} = \frac{0.005016}{0.001} = 5.016

(e) Time Interval [2.9999,3][2.9999, 3]:

  • s(2.9999)=16(2.9999)2+101(2.9999)=16(8.99940001)+302.9999=143.99040016+302.9999=159.00949984s(2.9999) = -16(2.9999)^2 + 101(2.9999) = -16(8.99940001) + 302.9999 = -143.99040016 + 302.9999 = 159.00949984

Now, the average velocity: vavg=159159.0094998432.9999=0.0005000160.0001=5.0016v_{\text{avg}} = \frac{159 - 159.00949984}{3 - 2.9999} = \frac{0.000500016}{0.0001} = 5.0016

3. Instantaneous Velocity at t=3t = 3:

To find the instantaneous velocity at t=3t = 3, we take the derivative of s(t)s(t): s(t)=ddt(16t2+101t)=32t+101s'(t) = \frac{d}{dt}(-16t^2 + 101t) = -32t + 101 Now, plug in t=3t = 3: s(3)=32(3)+101=96+101=5s'(3) = -32(3) + 101 = -96 + 101 = 5

So, the instantaneous velocity at t=3t = 3 is 5.

Would you like more details or have any further questions? Here are some related questions to expand on this:

  1. What is the difference between average and instantaneous velocity?
  2. How does taking the derivative of a position function give us velocity?
  3. How can we approximate the instantaneous velocity using smaller and smaller time intervals?
  4. How do we interpret negative values for velocity?
  5. What would the position graph of this function look like?

Tip: Instantaneous velocity is just the slope of the tangent line to the position-time curve at a given time!

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Math Problem Analysis

Mathematical Concepts

Calculus
Average Velocity
Instantaneous Velocity
Derivatives
Limits

Formulas

Average Velocity Formula: v_avg = (s(b) - s(a)) / (b - a)
Derivative of Position Function: s'(t) = -32t + 101

Theorems

Definition of Derivative
Limit Process to Instantaneous Velocity

Suitable Grade Level

Grades 11-12 or Early College