A 0.885-{\ m kg} ball is tied to the end of a string of length 1.54m and swung i
ID: 2187637 • Letter: A
Question
A 0.885-{ m kg} ball is tied to the end of a string of length 1.54m and swung in a vertical circle.Part A During one complete circle, starting anywhere, calculate the total work done on the ball by the tension in the string. Part B During one complete circle, starting anywhere, calculate the total work done on the ball by gravity.Part C Repeat part (a) for motion along the semicircle from the lowest to the highest point on the path. Part D Repeat part (b) for motion along the semicircle from the lowest to the highest point on the path. PLEASE PROVIDE ME ANSWERS I NEED TO MATCH THEMExplanation / Answer
a) Tension in the string: since the angle between the force of the string's tension and the motion of the ball at the end of the string is 90 degrees, cos(90 degrees) = 0. So NO WORK is done by the string. so, A) 0 b) Gravity: This is more complex: The motion of the ball about the vertical circle is sometimes in the direction of the gravitational pull (downward), sometimes in the opposite direction, and mostly in between. So, at any one moment, there is a calculation to be done. However, what makes the problem easy is that they are asking for the work done during ONE COMPLETE CYCLE. In that case, the answer is simple: over one complete cycle, the total displacement is zero, so the total displacement along the direction of gravity is also zero, so the total work done by gravity is zero. so B) 0 C) 0 D) W = -2R*m*g = -26.71 J
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