Answer:
[tex]P(t) = 50t +25[/tex]
[tex]t = 2.5s[/tex]
Explanation:
Given
See attachment for graph
Solving (a): The graph equation.
Pick two points on the line of the graph
[tex](t_1,P_1) = (0.9,70)[/tex]
[tex](t_2,P_2) = (0.7,60)[/tex]
Calculate the slope (m)
[tex]m = \frac{P_2 - P_1}{t_2 - t_1}[/tex]
[tex]m = \frac{60 - 70}{0.7 - 0.9}[/tex]
[tex]m = \frac{-10}{-0.2}[/tex]
[tex]m = 50[/tex]
The equation is then calculated using:
[tex]P(t) = m(t - t_1) + P_1[/tex]
[tex]P(t) = 50(t - 0.9) + 70[/tex]
[tex]P(t) = 50t - 45+ 70[/tex]
[tex]P(t) = 50t +25[/tex]
Solving (b): Solve for t when [tex]P(t) =150cm[/tex]
We have:
[tex]P(t) = 50t +25[/tex]
Substitute: [tex]P(t) =150cm[/tex]
[tex]150 = 50t + 25[/tex]
Collect like terms
[tex]50t = 150 - 25[/tex]
[tex]50t =125[/tex]
Divide both sides by 50
[tex]t = \frac{125}{50}[/tex]
[tex]t = 2.5s[/tex]