OnlineCBT
Physics · WORK, ENERGY AND POWER
हिन्दीGiven below are two statements: Statement I: When the angle \( \theta \) between the force vector and the displacement vector is obtuse (\( 90^\circ < \theta \le 180^\circ \)), the work done by the force is negative. Statement II: Kinetic energy of a particle of mass \( m \) moving with velocity \( \mathbf{v} \) is a vector quantity directed along the direction of motion. In the light of the above statements, choose the most appropriate answer from the options given below:
Correct answer · Option 3
Statement I is correct but Statement II is incorrect.
Explanation
Statement I is correct because \( \cos\theta < 0 \) for obtuse angles. Statement II is incorrect because kinetic energy is a scalar quantity, defined as \( K = \frac{1}{2}m(\mathbf{v}\cdot\mathbf{v}) \).
