Bob and Julie have gone to a park where there is a 5 m, 100 kg see saw (teeter totter), with the fulcrum located at x = 2 m, as shown below. Bob, whose mass is 35 kg, sits at the end on the 'short' side of the see saw (at x = 0), while Julie, whose mass is 20 kg, sits on the end on the 'long' side of the see saw (at x = 3 m). Where should a 30 kg weight be placed, relative to Bob on the x-axis, to make the see saw balance?
![A lab experiment is set up to investigate simple harmonic motion. A block is attached to an ideal spring, and it oscillates back and forth on a frictionless, horizontal surface. One end of the spring is fixed in place, and the other end of the spring is attached to the block, whose mass is 0.800 kg. The motion of the spring is expressed by x(t) = (0.100 m)cos[(17.0 rad/s)t]. When the block is at x = +0.070 m, its speed is closest to: A) 1.50 m/s B) 1.21 m/s C) 0.934 m/s D) 0.074 m/s E) None of these](https://www.doubtrix.com/uploads/editor/6647417383zoryBTIkyd.jpg)
