<p>The figure below shows a thin rod, of length<em>L</em> = <span style="color:red;">1.9</span> m and negligible mass, that can pivotabout one end to rotate in a vertical circle. A heavy ball of mass<em>m</em> = <span style="color:red;">4</span> kg is attached to the other end. The rod ispulled aside through an angle <span style="font-family:georgia;"><em>θ</em></span> =<span style="color: red;">22</span><spanstyle="color: #dd0000;">°</span> and releasedwith velocity <span style="text-decoration: overline;font-style: italic;">v</span> = 0. Answer the followingquestions assuming the ball is at its lowest point.</p>
<div class="figure"><imgsrc="http://www.webassign.net/hrw/08_32.gif" alt=""/></div>
<p>(a) how much work does its weight do on it. <br /><span class="qTextField"> <span class="box_num"style="display: none;" title="Points:/1">1</span><input id="RN_1022317_2_0_1031200"dir="ltr" name="RN_1022317_2_0_1031200" size="10" type="text"value="-4" /></span><imgid="mark_RN_1022317_2_0_1031200" title="Your answer was incorrect,but has changed from what was graded."src="http://www.webassign.net/wastatic/common/img/cross_grey3.png"alt="Your answer was incorrect, but has changed from what wasgraded." /> J<br /><br /> (b) what is the change inthe gravitational potential energy of the ball Earth system?<br/> <span class="qTextField"> <span class="box_num"style="display: none;" title="Points:/1">2</span><input id="RN_1022317_2_1_1031200"dir="ltr" name="RN_1022317_2_1_1031200" size="10" type="text"/></span> J<br /><br /> (c) If thegravitational potential energy is taken to be zero at the lowestpoint, what is its value just as the ball is released?<br /><span class="qTextField"> <span class="box_num"style="display: none;" title="Points:/1">3</span><input id="RN_1022317_2_2_1031200"dir="ltr" name="RN_1022317_2_2_1031200" size="10" type="text"/></span></p>
J