Question

An object in shm oscillates with a period of 4.0s and an amplitude of 11 cm . part a how long does the object take to move from x = 0.0 cm to x = 6.5 cm .

Answer 1

If the Amplitud is 11×2=22cm and the wave was in shm then we can get the wavelength as 11×2=22s.
From the wave equation, 

v=fλ Where v⇒speed
                    f⇒frequency and 
                    λ⇒Wavelength

And we know that; 
f=1/T
f = 1/4 =0.25 Hz
∴v = 0.25 ×22 = 5.5 cm/s

Since we know know the speed of the object we can get its time it takes from (0-6.5) cm.

v = fλ = λ/T

∴T = λ/v
     = 6.5/5.5
      = 1 2/11
      = 1.181818s

The time taken for the object to move from x = 0.0 cm to x = 6.5 cm is 1.181818s