Not a Scalar Quantity: Impulse

Scalar and Vector Quantities
Scalars are physical quantities that have only magnitude and no direction, and they can be positive or negative. Examples of scalar quantities include temperature, speed, energy, mass, time, and distance. On the other hand, vector quantities are physical quantities that have both magnitude and direction, and they can be represented by arrows. Examples of vector quantities include force, velocity, acceleration, displacement, and momentum.

Impulse as a Vector Quantity
Impulse is a vector quantity that is defined as the change in momentum of an object when a force is applied to it for a certain amount of time. It is represented by the symbol J, and its units are newton-seconds (Ns) or kilogram-meters per second (kg·m/s). Impulse is a vector quantity because it has both magnitude and direction, and it is in the same direction as the force that causes it.

Example of Impulse as a Vector Quantity
Suppose a tennis ball of mass 0.05 kg is hit by a racket with a force of 50 N for 0.01 seconds. The impulse experienced by the ball is given by J = FΔt = (50 N)(0.01 s) = 0.5 Ns. The direction of the impulse is the same as the direction of the force, which is perpendicular to the surface of the racket. Therefore, the impulse is a vector quantity.

Conclusion
In conclusion, impulse is not a scalar quantity because it has both magnitude and direction, and it is represented by a vector. Scalar quantities have only magnitude and no direction, and they can be positive or negative. Therefore, the correct answer to the question is option D, impulse.