Amodel of a sailing yacht is towed with a small angle of attack, or leeway angle, about the vertical axis. the drag force and side force are measured separately. if the yacht hull operating in this manner can be regarded as a vertical hydrofoil in the presence of the free surface, what are the appropriate scaling laws to apply to each force component? distin- guish between parameters that should be scaled in principle and those that would be most important in a model test. in fresh water (15°c), towing- tank tests of a model 2 m long with wetted-surface area 1.5 m² give a measured drag force of 10 n and a side force of 28 n at a speed of 1.4 m/s. what are the corresponding full-scale results for a yacht 10 m long in salt water (15°c)?

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

An electrical motor raises a 50kg load at a construct velencity .calculate the power of the motor, if it takes 40sec to raise the load through a height of 24m(take g =9.8n/g)

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.