IB-Wheel trigonometry problem

[Leah5467]

Hello! It is me again. ?i don't really understand this question:

i have found the answer of 10sin(pi/50(t-25))+2,and i checked the answer and it said that d should be 12. I don't understand why.

Thank you!

 

[Harry_the_cat]

OK best thing to do is to draw a graph of the height(h) against time (on the horizontal axis).
When t=0 what is h ?
When t=100, what is h?
When the light is at the highest point, what is h? and what is t?
When the light has done one quarter of a revolution what is h? what is t?
What about three quarters of a revolution?
Plot the points and join up with a sinusoidal curve.
That should help you see why d=12.

 

[Leah5467]

ohhh i see! Thank you so much for always helping me!