A 74.7kg man steps off a platform 3.03m above the ground. He keeps his legs straight as he falls, but at the moment his feet touch the ground his knees begin to bend, and, treated as a particle, he moves an additional 0.600m before coming to rest.
Here's what I got so far:
Part A- his speed at the instant his feet touch the ground: v=7.71m/s
Part B- Treating him as a particle, the magnitude of his acceleration as he slows down if the acceleration is constant: a=49.5m/s^2
Part C- Treating him as a particle, the direction of his acceleration as he slows down if the acceleration is constant is upward
Part D- Using Newton's laws and the results of part B to calculate the force the ground exerts on him while he is slowing down: F=4430N
The Physics of sports - Google Books Result::
href=http://books.google.com/books?id=CPosYIEgag8C&pg=PA200&lpg=PA200&dq=Physics-+Jumping+to+the+ground%3F&source=bl&ots=-ysSu-t1a2&sig=hVxoGYp-vZ3UMKPXy6Ljit6rYow&hl=en&ei=b-1-SrDiBI_-tQP6vLjvCg&sa=X&oi=book_result&ct=result&resnum=49 class=l onmousedown=return clk(http://books.google.com/books?id=CPosYIEgag8C&pg=PA200&lpg=PA200&dq=Physics-+Jumping+to+the+ground%3F&source=bl&ots=-ysSu-t1a2&sig=hVxoGYp-vZ3UMKPXy6Ljit6rYow&hl=en,,,res,72,)>The Physics of sports - Google Books Resultby Angelo Armenti - 1992 - Science - 333 pagesMAXIMUM HEIGHT OF VERTICAL JUMP The event needs a bit of explanation. The work done on the body is done by the ground exerting a force on the jumper
http://books.google.com/books?id=CPosYIEgag8C&pg=PA200&lpg=PA200&dq=Physics-+Jumping+to+the+ground?&source=bl&ots=-ysSu-t1a2&sig=hVxoGYp-vZ3UMKPXy6Ljit6rYow&hl=en&ei=b-1-SrDiBI_-tQP6vLjvCg&sa=X&oi=book_result&ct=result&resnum=49HOME |
Part E- Using Newton's laws and the results of part B to calculate the force the ground exerts on him while he is slowing down. This force as a multiple of the man's weight: F= 6.05 W
Question:
What is the magnitude of the reaction force to the force you found in part E?
Excel Preliminary Physics - Google Books Result::
href=http://books.google.com/books?id=Tbx4qOkWwgwC&pg=PA129&lpg=PA129&dq=Physics-+Jumping+to+the+ground%3F&source=bl&ots=GmsHx6mTbQ&sig=IPzLLsAb1LM3OrhrkTJ-giAF11Y&hl=en&ei=b-1-SrDiBI_-tQP6vLjvCg&sa=X&oi=book_result&ct=result&resnum=13 class=l onmousedown=return clk(http://books.google.com/books?id=Tbx4qOkWwgwC&pg=PA129&lpg=PA129&dq=Physics-+Jumping+to+the+ground%3F&source=bl&ots=GmsHx6mTbQ&sig=IPzLLsAb1LM3OrhrkTJ-giAF11Y&hl=en,,,res,36,)>Excel Preliminary Physics - Google Books Resultby Neville G. Warren - 2000 - Science - 257 pagesMOMENTUM AND FORCE When you jump to the ground from a height, you intuitively bend your knees on contact with the ground rather than keeping your knees
http://books.google.com/books?id=Tbx4qOkWwgwC&pg=PA129&lpg=PA129&dq=Physics-+Jumping+to+the+ground?&source=bl&ots=GmsHx6mTbQ&sig=IPzLLsAb1LM3OrhrkTJ-giAF11Y&hl=en&ei=b-1-SrDiBI_-tQP6vLjvCg&sa=X&oi=book_result&ct=result&resnum=13HOME |
F(reaction) = ??
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Physics- Jumping to the ground?