Question

A mass m =100 gms is attached at the end of a light spring which oscillates on a frictionless horizontal table with an amplitude equal to 0.16 metre and time period equal to 2 sec. Initially the mass is released from rest at t = 0 and displacement $x = - 0.16$ metre. The expression for the displacement of the mass at any time t is

• A. $x = 0.16 \cos ( \pi t )$
• B. $x = - 0.16 \cos ( \pi t )$
• C. $x = 0.16 \sin ( \pi t + \pi )$
• D. $x = - 0.16 \sin ( \pi t + \pi )$

Answer 1

Answer: (B)

$x = - 0.16 \cos ( \pi t )$

Answer 2

Standard equation for given condition

$x = a \cos \frac { 2 \pi } { T } t$ ⇒ $x = - 0.16 \cos ( \pi t )$

[As a = – 0.16 meter, T = 2 sec]