13.2 m/s
Step-by-step explanation
Step 1
Diagram
the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. so, if we ignore the friction, we can se apply this to set an equation
a) At a , the rollercoaster has
potential gravitational energy ( due to the heigth), as it start from the rest the velocity is zero,s o the kinetick energy is zero
b) at B, the rollercoster has
potential gravitational energy ( due to the heigth) and kinetick energy ( due to its mass ena velocity)
hence
Step 2
let
replace and solve for v
so
therefore, the answer is
13.2 m/s
I hope this helps you