5 A graphing calculator is recommended If a rock is thrown upward on the planet Mars with a velocity 8 m s its height in meters t seconds later is given by y 8t 1 86t2 Round your answers to two decimal places a Find the average velocity in m s over the given time intervals 1 1 2 1 1 1 5 1 1 1 iv 1 1 01 v 1 1 001 m s m s m s m s m s b Use your answers from part a to estimate the instantaneous velocity of the rock in m s when t 1