A particle executing SHM of amplitude 4 cm and T = 4 sec. The time taken by it to move from positive extreme position to half the amplitude is
1sec
1/3sec
2/3sec
3/2sec
Equation of motion y=acosωt
⇒ a2=acosωt⇒cosωt=12⇒ωt=π3⇒ 2πtT=π3⇒t=π3×T2π=43×2=23sec