Physics
A range in a national park is driving at 47 km/h when a deer jumps onto the road 70m ahead of the vehicle . After a reaction of t seconds, the ranger applies the brakes to produce an acceleration of -2.00 m/s^2. What is the maximum reaction time allowed if the ranger is to avoid hitting the deer?
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The maximum reaction time allowed is 2.3 seconds. This is because to avoid hitting the deer, the ranger needs to stop the vehicle before it covers the 70 m of distance. The ranger can achieve this by applying the brakes shortly after the deer appears, to slow the car down. Since the car is moving at 47 km/h at the start, this is equivalent to 13.1 m/s. With an acceleration of -2.00 m/s^2, this means that in order to cover a distance of 70 m, the reaction time must not exceed 2.3 seconds.
