William is walking straight across a field towards a vertical flagpole .He observes that when he is at point A ,the angle of elevation of T, the top of the flagpole is 30degrees and when he is at point B, on the same side of the flagpole as A, the angle of elevation of T is 45degrees .The distance between A and Bis 20 metres . Using a scale of 1cm to represent 4m ,construct a single diagram to show the relative positions of A, B and T .b. Using a suitable construction on the same diagram, find the height of the flagpole

The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)