A motorist is traveling at 25m/s.He is 60 m from a stop light when he sees it turns yellow. His reaction time, before stepping on the brake is 0.5 s.

a)What steady deceleration while braking will bring him to a stop right at the light?

b)If the motorist reaction time was 0.65 S. what would be his velocity when he reaches to the traffic light with same acceleration as part a?

Please provide work, formulas, units, thank you