log problem

I have a question I need help with, please help me out guys

If a coil spring is stretched 1.5m beyond its resting point and then released it will return to a point which is 90% of the previous distance from the resting point. How many vibrations are required before the spring moves less than 10 cm from its resting point?

THANK YOU!!

Jeepers that's a geometric sequence 1.5, (0.9)1.5, (0.9)(0.9)1.5, etc.

general term, nth term = 1.5(0.9)^(n-1)

solve for n with 0.10 = 1.5(0.9)^(n-1)

Use logarithms to help solve because the unknown is in the exponent position.  Also, round n up to next whole number to make be less than 10 cm.