A human "cannon ball" in the circus is shot at a speed of 21.0 m/s at an angle of 20 degrees above the horizontal from a platform that is 15.0m above the ground.(adsbygoogle = window.adsbygoogle || []).push({});

a. If the acrobat has a mass of 56.0 kg, what is his gravitational potential energy relative to the ground when he is at the highest point of his flight? Ignore the effects of air resistance. (Ans: 9.69X10^3 J)

b. If the net in which he lands is 2.00 m above the ground, how fast is he travelling when he hits it? (Ans: 26.4m/s)

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[Ek=Kinetic Energy, Ep=Potential Energy, Em=Total Energy]

Ep=mgh

Ek=1/2mv^2

W=Fd

Em=Ep+Ek

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I have found both the Ep and Ek values and added he values up, but the answer isn't anywhere near close. There is something more to it I believe, but I'm not even fully sure how Potiential energy and Kinetic energy are related. I have no idea whether the angle is relevant or not eithier. Explanations would be great help.

Help would be much appreciated. Thanks~

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# Homework Help: Kinetic/Potential/Mechanical Energy Problems

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