A) Demuestre que si la caída de presión permanece constante, la reducción del radio de la arteriola de 0,1 a 0,08 mm disminuye el flujo sanguíneo en un factor superior a 2. b) Calcule la disminución del radio necesaria para reducir el flujo sanguíneo en un 90%. Alguien que me ayude por favor

You are driving to the grocery store at 20 m/s. you are 110m from an intersection when the traffic light turns red. assume that your reaction time is 0.50s and that your car brakes with constant acceleration. how far are you from the intersection when you begin to apply the brakes? what acceleration will bring you to rest right at the intersection? how long does it take you to stop after the light changes? the known values: vi=20m/s xi=110m t=.50s vf=0m/s xf=0m a=?