Simple harmonic motion block and spring

[banfill_89]

Homework Statement

A block, attached to a spring, is set into vertical oscillation with an amplitude of 25.0 cm and a frequency of 5.00 Hz. At t = 0.00 s, the block is 14.0 cm below the equilibrium position and is moving upwards. Assume that the displacement from equilibrium is given by
y = ym cos(ω t + φ ) , with y positive upwards.
Calculate the phase angle, φ.
(a) 5.31 rad
(b) 0.976 rad
(c) 4.12 rad
(d) 2.17 rad
(e) 1.87 rad

the answer is c...

Homework Equations

ive been using the equation that was given to me in the question, using 0.14m as my y, 0.25m as my ym, 0 as my t therefore w isn't needed? and i have a frequency? I am lost...please help lol

i am arriving at (b)...if this helps at all

The Attempt at a Solution

 

[turin]

Did you use the fact that the block is moving upwards? Here's a hint: what is the numerical difference between b and c? Does it look familiar?

 

[banfill_89]

pi lol...do i have to add pi? confusion

 

[turin]

do i have to add pi?

That was only a hint. Forget about \pi.

EDIT: Your y is wrong. Can you tell me why? (haha)

EDIT: EDIT: Wait a minute! THEIR y is wrong! Are you sure you copied every word of the problem correctly?