Since
<span>Vf^2 = 2*a*S </span>
<span>Given S=3.6m, thus </span>
<span>a = Vf^2/(2*3.6) </span>
<span>a = Vf^2/7.2 </span>
<span>Let d be the distance along the slope at which the velocity is 0.5Vf, then </span>
<span>(0.5Vf)^2 = 2*a*d </span>
<span>or </span>
<span>d = (0.5*Vf)^2/(2*a) </span>
<span>with a = Vf^2/7.2, we have </span>
<span>d = 0.9 m</span>
simple harmonic motion is a special type of periodic motion or oscillation where the restoring force is directly proportional to the displacement and acts in the direction opposite to that of displacement.
An example you could use for this would be if you threw a pencil across the room 10m away. the pencil would have travelled 10m(N). you could determine the objects speed by using the formula speed=distance/time. you would have had to time how long it took for the pencil to hit the 10m marking and divide 10 by however many seconds it took.