What Causes Oscillation Errors in Air-Track Glider Experiments?

[animanga008]

An air-track glider is attached to a spring. The glider is pulled to the right and released from rest at t=0. It then oscillates with a period of 1.50 s and a maximum speed of 46.0 cm/s.

I found the amplitude to be 11cm (this is 100% correct)

1) What is the glider's position at t= 26.0 s?

How do i do #1?

I used the formula x = A cos ( wt) and plugged everything in.

x = (11cm) cos (26sec x 2pie/1.5)
x = -3.56

but my answer is wrong :-(

 

[AlephZero]

Your angle 26*2*pi/1.5 is in radians, but I think your calculator was set to work in degrees.