PHYS 2001 Chapter : 170125 Kutter Ch2 2
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This is the equation for motion under constant acceleration! By using the definition of acceleration, , i can solve this for t: v o a v f t t v f v o a. Now plug this in for t in the above equation and do some algebra. This equation gives the relationship between distance, acceleration, and the initial and final velocities. First, let"s convert 90 km/hr to m/s: v o. You have a reaction time of 0. 75 s, so the car moves closer to the cow by an amount: This only leaves: 30 m 18. 75 m = 11. 25 m of distance left to the cow. Given the deceleration of the car, what will its final velocity. We know a, we know x, and we know vo. Example: you are driving along in the country at 90 km/hr, when you suddenly notice a cow in the road 30 m ahead.