When the boat moves on the surface of the water the resistance force of the environment F is directly proportional to the speed v (
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, where
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- coefficient of proportionality). At the moment of the engine shutdown the outboard motorboat is moving at a speed of 224 m/min., and 1 min. later it’s speed is equal to 112 m/min. 4 min. after the engine shutdown the outboard motorboat will be moving at a speed of ______ m/min..