Answer:
[tex]-5m/s^2[/tex], the negative sign is an indication that the roller coaster is decelerating.
Explanation:
Acceleration or deceleration is define as the rate of change in the velocity of a body. It is given by the following relationship;
[tex]a=\frac{v-u}{t}............(1)[/tex]
where v is the final velocity, u is the initial velocity and t is the time taken.
Given,
v = 10m/s
u = 25m/s
t = 3s
hence
[tex]a=\frac{10-25}{3}\\a=-5m/s^2[/tex]