Consider the rock and string in Figure P6.43. The string is fastened to a hinge that all...

Consider the rock and string in Figure P6.43. The string is fastened to a hinge that allows it to swing completely around in a vertical circle. If the rock starts at the lowest point on this circle and is given an initial speed ,what is the smallest value of that will allow the rock to travel completely around the circle without the string becoming slack at the top? Assume the length of the string is 1.5 m.