Answer :
We are given that a car travels in circular motion is a semi-circle of radius 291 m and longitude of 915 m. To determine the centripetal acceleration we will use the following formula for the centripetal acceleration in a circular motion:
[tex]a=\frac{v^2}{r}[/tex]Where:
[tex]\begin{gathered} a=\text{ acceleration} \\ v=\text{ velocity} \\ r=\text{ radius} \end{gathered}[/tex]To determine the velocity we will use the fact that the car travels at a constant speed, therefore, the velocity is the quotient of the longitude of the track and the time it takes the car to travel through it:
[tex]v=\frac{s}{t}[/tex]Where:
[tex]\begin{gathered} s=\text{ longitude} \\ t=\text{ time} \end{gathered}[/tex]Now we plug in the values:
[tex]v=\frac{915m}{15s}[/tex]Solving the operations we get:
[tex]v=61\frac{m}{s}[/tex]Now we use this value in the formula for the acceleration:
[tex]a=\frac{(61\frac{m}{s})^2}{291m}[/tex]Now we solve the operations and we get:
[tex]a=12.79\frac{m}{s^2}[/tex]Therefore, the centripetal acceleration of the car is 12.79 meters per second squared.