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Q1. (a) A ship is scheduled to complete a journey of 540 nautical miles at an average speed of 12 knots. It covers the first quarter of the journey at an average speed of 13.5 knots. However due to a series of factors its speed in the last three quarters of the journey is reduced and it arrives at its destination 1 hour 40 minutes late.

Calculate the average speed of the ship over the second part of its journey. (8)

(b) The wind force W on a vertical surface varies directly as the area, A m², of the surface and directly as the square of the wind velocity, v km/hr. When the wind speed is 36 km/hr the force on an area of 2.5 m² is 320 Newtons.

Calculate the force on a surface of area 4 m² when the wind speed is 60 km/hr. (8)