4v2=25−x2
Differentiating,
vdvdx×8=−2x
or acceleration =dvdt=dvdxdxdt=vdvdx=−x4
So, acceleration is proportional to displacement and directed towards the fixed point. So, it executes SHM.
∴d2xdt2=−x4
Comparing it with d2xdt2=−ω2x⇒ω2=14
∴ω=12
∴T= period =2πω=2π1/2=4π sec