Emily WeimerBiomechanics Laboratory CProjectile MotionPart 1 - Se n siti v ity o f p e rf o r m a n ce to s p eed, a ng le, and h e i g h t Release conditions Flight 1 Flight 2 Average“speed”angleheight ShShShNominal case 12 cm 20° Floor 167.64 148 157.82+25% speed 15 cm 20° Floor223 238 230.5+50% angle 12 cm 30° Floor193 189 191+170% height 12 cm 20° Floor + box161 200 180.5 Which manipulation provides the best benefit based on % increase? Compute the percent change in horizontal displacement (Sh) of the projectile you would expect if you increased “speed,” angle, or height by 20% manipulations compared with the nominal case: +20% speed = 36.84% - provides best benefit based on % increase +20% angle = 8.41% +20% height = 1.69%Quest i ons to be answer e d: 1. a) Horizontal displacement was most sensitive to which of the three release factors? Explain why the horizontal displacement was most sensitive to this release factor (Hint: consider how vv, vh and ttot are affected by changing the release factors, noting that sh = vh ttot and increases ineither vv or height will increase ttot)Out of the three different release factors, horizontal displacement was most sensitive to the speed of release. Increasing the release speed results in increased an increased horizontal and vertical velocity, which results in an increased horizontal displacement. Increasing the speed also increases the amount of time the rubber band will spend in the air. Part 2 – Different solutions to the same problem “Speed” AngleCase 1 14 cm 25Case 2 15 cm 10Quest i on to be answer e d :3. Based on your results, des c ribe how speed affects technique (reflected by release angle) and horizontal displacement (max sh)? Through this trial-and-error process of finding the right speed and angle to hit the target we were able to see how speed affected both horizontal displacement and release angle. In order to hit the target, we had to increase the speed, which also required us to increase the angle of the launch. We were then able to increase the speed 1 cm, which required us to decrease the angle by 15 degrees. Although horizontal displacement is affected greater by increasing speed, if we had increased the speed by 1 and hadn’t decreased the angle then the rubber band would’ve flown over the target, showing that the technique (release angle) also influences the horizontal displacement. Part 3 - T h e real t h in g : A c o llisi o n b e t w een t h eory and realit y? Trail # Goal AngleActual AngleSpeed Height VvVhTtotSh1 10 deg 11.4 deg 8.27 m/s 1.62 m 1.63 m/s 8.11 m/s .765 s 6.2 m2 20 deg 20.4 deg 7.38 m/s 1.87 m 2.57 m/s 6.92 m/s .933 s 6.45 m3 30 deg 29.6 deg 6.44 m/s 2.08 m 3.18 m/s 5.6 m/s 1.05 s 5.89 m4 35 deg 35.9 deg 5.93 m/s 2.22 m 3.48 m/s 4.8 m/s 1.11 s 5.36 m5 45 deg 44.1 deg 5.35 m/s 2.35m 3.72 m/s 3.84 m/s 1.17 s 4.49 mQuestion to be answered:4. What happened to the speed and height of release as the angle of release was increased? Were these changes what you would expect to observe? E xplai n .The speed decreased as the angle of release and height was increased. The horizontalvelocity is less when the height of release is increased because the speed also decreases.Having an increase in height increases the vertical velocity, which will result in a decreasedhorizontal displacement, and horizontal velocity. After conducting a few trials of adjustingthe rubber band height and speed I was able to understand why this was happening. 5. Which of the five cases resulted in the greatest horizontal displacement? Does thismake sense? E xplai n. The horizontal displacement was greatest in the second case. When using the formula sh = vh ttot, the greatest displacement is seen in the second case. The speed and releaseangle used in the second case result in the projectile being able to travel the further
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