A runner and his trainer are standing together on a circular track of radius 100m. When the trainer gives a signal, the runner starts to run around the track at a speed of 10m/s. How fast ( in m/s) is the distance between the runner and the trainer increasing when the runner has run 1/4 of the way around the track?
Solution:
im following the solution on this book (found this on google)
http://books.google.com.ph/books?id=D5um9mN-JAsC&pg=PA133&lpg=PA133&dq=a+runner+and+his+trainer+are+standing+together+on+a+circular+track+of+radius+100m.+when+the+trainer+gives+a+signal,+the+runner+starts+to+run+around+the+track+at+a+speed&source=bl&ots=UVaTZ1uy-O&sig=VZ7QXn_-pxLYVc9_0EV15884DFs&hl=tl&ei=rJvgToq3FsKQiAfkhPy_BQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBoQ6AEwAA#v=onepage&q&f=false
however im confused to how they get this relation:
\(\displaystyle x\frac{dx}{dt} = 10000\sin(\theta) \frac{d\theta}{dt}\)
edit
law of cosines
nevermind this thread
Solution:
im following the solution on this book (found this on google)
http://books.google.com.ph/books?id=D5um9mN-JAsC&pg=PA133&lpg=PA133&dq=a+runner+and+his+trainer+are+standing+together+on+a+circular+track+of+radius+100m.+when+the+trainer+gives+a+signal,+the+runner+starts+to+run+around+the+track+at+a+speed&source=bl&ots=UVaTZ1uy-O&sig=VZ7QXn_-pxLYVc9_0EV15884DFs&hl=tl&ei=rJvgToq3FsKQiAfkhPy_BQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBoQ6AEwAA#v=onepage&q&f=false
however im confused to how they get this relation:
\(\displaystyle x\frac{dx}{dt} = 10000\sin(\theta) \frac{d\theta}{dt}\)
edit
law of cosines
nevermind this thread
Last edited: