an object oscillates as it moves along the x-axis. it's displacement varies with time according to the equation x=4sin (pi t + pi/2) where t=time in seconds and x= displacement in meters what is the displacement between t=0 and t=1second?

Ahanging spring stretches by 35.0 cm when an object of mass 450 g is hung on it at rest. in this situation, we define its position as x = 0. the object is pulled down an additional 18.0 cm and released from rest to oscillate without friction. what is its position x at a moment 84.4 s later? express your answer in cm.