Question

A particle is an linear simple harmonic motion between two extreme point A and B. 10 cm apart(See figure below) If the direction from A to B is taken as positive direction, what are signs of displacement x, velocity V and acceleration a, when the particle is at A?

• A. $x=-ve,V=-ve,a=-ve$
• B. $x=+ve,V=0,a=-ve$
• C. $x=+ve,V=-ve,a=+ve$
• D. $x=-ve,V=0,a=+ve$

Answer 1

The correct option is D $x=-ve,V=0,a=+ve$

When particle is at extreme A, velocity is zero. Since it is on the negative side of the mean, thus x is negative. Acceleration will be towards right that pulls it back (= - kx), thus acceleration is positive (as x is negative).