The rigid bar is pinned at a and supported by two aluminum rods, each having a diameter of 1 in. a modulus of elasticity eal = 10(103) ksi, and yield stress of (sy)al = 40 ksi. if the bar is initially vertical, determine the angle of tilt of the bar when the 20-kip load is applied.

It indicates no change in temperature and the process of matter changing its state

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Since the pully is a simple machine so the mechanical advantage is a 1

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)