As shown in the figure, a car starts from o point and runs eastward at a constant speed of 100 km / h along a straight road along the coast. When the car starts, there is a speedboat at m on the sea 500 km south by east of o point and 300 km away from the coast MQ. Starting at the same time with the car, to deliver an important item to the driver of the car, ask at least what speed the speedboat must travel Only when the speedboat is running at the minimum speed, can the goods be delivered to the driver

As shown in the figure, a car starts from o point and runs eastward at a constant speed of 100 km / h along a straight road along the coast. When the car starts, there is a speedboat at m on the sea 500 km south by east of o point and 300 km away from the coast MQ. Starting at the same time with the car, to deliver an important item to the driver of the car, ask at least what speed the speedboat must travel Only when the speedboat is running at the minimum speed, can the goods be delivered to the driver

Let the speedboat sail in Mn direction at the speed of V km / h from m, and meet the car after t hours. In △ Mon, Mo = 500, on = 100t, Mn = vt. let ∠ mon = α, from the topic meaning, we know sin α = QMOM = 35, then cos α = 45