SOLUTION: Can you help me to solve and understand this problem. please: A Ferris wheel 70 feet in diameter completes one revolution every 58 seconds. Its central point is 40 feet above the

Algebra ->  Trigonometry-basics -> SOLUTION: Can you help me to solve and understand this problem. please: A Ferris wheel 70 feet in diameter completes one revolution every 58 seconds. Its central point is 40 feet above the       Log On


   



Question 1124245: Can you help me to solve and understand this problem. please:
A Ferris wheel 70 feet in diameter completes one revolution every 58 seconds. Its central point is 40 feet above the ground.
a) write a sinusoidal function H(t) to model a rider's height above ground as a fusion of time t in seconds.
b) how long does. it take a rider to go from the lowest point of travel to 61 feet above the ground?

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
If you spin a radius vector, +r+, at the origin,
It traces out a sine wave plotted on the time axis.
It has a -r to +r height, so the height is +2r+
——————
In your problem, +2r+=+70+ and +r+=+35+
If the Ferris wheel was at ground level, the
function would be +f%28t%29+=+35%2Asin%28+%28+2pi%2F58+%29%2At+%29+,
but they want the center +40+ ft above ground,
So the function is: +H%28t%29+=+35%2Asin%28+%28+2pi%2F58+%29%2At+%29+%2B+40+
——————-
b)
Find +t+ when +H%28t%29+=+61+
+61+=+35%2Asin%28+%28+2%2Api%2F58+%29%2At+%29+%2B+40+
+35%2Asin%28+%28+2%2Api%2F58+%29%2At+%29+=+21+
+sin%28+%28+2%2Api%2F58+%29%2At+%29+=+.6+
If this was:
+sin%28+theta+%29+=+.6+ then, in radians,
+theta+=+.6435+ radians ( calculator )
Now I can say:
+%28+2%2A3.14159%2F58+%29%2At+=+.6435+
+.10833%2At+=+.6435+
+t+=+5.9402+ sec
———————————
Here’s a plot:

Note that with this curve, you would have to get on
the Ferris wheel at the 58 sec time. If you used -cos instead of
sin, then you get on at the zero time mark
Hope all this helps