Answer:
5 seconds
Explanation:
Acceleration, [tex]a=\frac {v-u}{t}[/tex]
Where v and u are the final and initial velocities of the roller coaster respectively, t is the time taken for the coaster to reach the top of the hill.
Making t the subject then
[tex]t=\frac {v-u}{a}[/tex]
Substituting -3 m/s2 for a since it decelerates, 25 m/s for u, then 10 m/s for v then
[tex]t=\frac {10-25}{-3}=5 s[/tex]
