NEET2016PhysicsMotion in One DimensionActual
A particle moves so that its position vector is given by r → = c o s ω t   x ^   + s i n ω t   y ^ , where ω is a constant. Which of the following is true?
Options
- AVelocity and acceleration both are perpendicular to r → .
- BVelocity and acceleration both are parallel to r → .
- CVelocity is perpendicular to r → and acceleration is directed towards the origin.
- DVelocity is perpendicular to r → and acceleration is directed away from the origin.
Correct answer
C. Velocity is perpendicular to r → and acceleration is directed towards the origin.
Step-by-step solution
Position vector is, r → = cos ⁡ ω t x ^ + sin ⁡ ω t y ^ Velocity of particle is v → = d r → d t v → = -sinω t × ω x ^ + cosω t × ω y ^ ⇒ v → = ω - sinω t x ^ + cosω t y ^ Acceleration of the particle is a → = d v → d t ⇒ a → = - ω 2 cosω t x ^ + sinω t y ^ ⇒ a → = - ω 2 r → , So direction of r → and a → are opposite. As v → · a &#