Rate of change question (The springs at the edge of a trampoline)

[AcridSuperset]

[FONT=&quot]The springs at the edge of a trampoline with supports 2m square stretch when a person lands on the mat. Someone bouncing to a height of 2.5m above the mat level returns to the mat with a speed of about 7m/s. Assuming that the person lands in the middle of the trampoline, and that the springs stretch evenly on each side, find the rate at which the springs are stretching when the person pushes the centre down 2cm but has little change of speed.[/FONT]

 

[tkhunny]

You should draw a triangle and add a coordinate system. Please show your work. Forum Guidelines, and all.