Question

suppose that a ball is rolling down a ramp. the distance traveled by the ball is given by the function s(t)=9t², where t is the time, in seconds, after the ball is released, and s(t) is measured in feet. find the balls average velocity in each of the following time intervals.
a. t₁ = 4 to t₂ = 5
δs/δt = 81 ft/sec
b. t₁ = 4 to t₂ = 4.5
δs/δt = 76.5 ft/sec
c. t₁ = 4 to t₂ = 4.01
δs/δt = ft/sec (type an exact answer, using integers or decimals.)

Explanation:

Step1: Recall average - velocity formula

The average velocity $\frac{\Delta s}{\Delta t}=\frac{s(t_2)-s(t_1)}{t_2 - t_1}$, where $s(t)=9t^{2}$.

Step2: Calculate $s(t_1)$ and $s(t_2)$

Given $t_1 = 4$ and $t_2=4.01$, then $s(t_1)=9\times4^{2}=9\times16 = 144$ and $s(t_2)=9\times(4.01)^{2}=9\times16.0801 = 144.7209$.

Step3: Calculate average velocity

$\frac{\Delta s}{\Delta t}=\frac{s(t_2)-s(t_1)}{t_2 - t_1}=\frac{144.7209 - 144}{4.01 - 4}=\frac{0.7209}{0.01}=72.09$

Answer:

$72.09$