Respuesta :
Answer:
[tex]\large \boxed{\text{60 s}}[/tex]
Step-by-step explanation:
Assume your graph looks like the one below.
1. Calculate the equation of the straight line
The slope-intercept equation for a straight line is
y = mx + b
where m is the slope of the line and b is the y-intercept.
The line passes through the points (0,2600) and (30, 2300)
(a) Calculate the slope of the line
[tex]\begin{array}{rcl}m & = & \dfrac{y_{2} - y_{1}}{x_{2} - x_{1}}\\\\ & = & \dfrac{2300 - 2600}{30 - 0}\\\\& = & \dfrac{-300}{30}\\\\& = & \text{-10 ft/s}\\\\\end{array}[/tex]
(b) Locate the y-intercept
The y-intercept is at 2600 ft
(c) Write the equation for the line
h = -10t + 2600
(d) Calculate the time to 2000 ft
[tex]\begin{array}{rcl}h & = & -10t + 2600\\2000 & = & -10t + 2600\\-600 & = & -10t\\t & = & \dfrac{-600}{-10}\\\\& = & \text{60 s}\\\end{array}\\[/tex]
Shelley will be at 2000 ft 60 s after opening the parachute.
Let the given line pass through the point that is [tex]\bold{(0,2600)\ \ and\ \ (20, 2400)}[/tex]
[tex]\therefore[/tex]
[tex]\to \bold{\frac{H-2400}{t-20}} \bold{= \frac{2600-2400}{0-20}}\\\\[/tex]
[tex]\bold{=\frac{200}{-20} }\\\\ \bold{= -\frac{200}{20}}\\\\ \bold{= - 10}\\\\[/tex]
[tex]\to \bold{H-2400=-10t+200}\\\\\to \bold{H+10t=2400+200}\\\\\to \bold{H+10t=2600}\\\\\to \bold{H=2600-10t}\\\\[/tex]
Let
time (t) in second
Height (h) in feet
for [tex]\bold{\ H=2000\ feet\\}[/tex]
[tex]\to \bold{2000=2600-10t}\\\\\to \bold{10t = 2600- 2000}\\\\\to \bold{10t = 600}\\\\\to \bold{t=\frac{600}{10}}\\\\\to \bold{t= 60\ second}\\\\[/tex]
Learn more:
brainly.com/question/3012638