Identify the correct statement from the following :

1. The average speed of a body can be zero even if it's average velocity is not zero.

2. Speed and velocity both are scalar quantities.

3. The magnitude of velocity of a body in motion is its speed.

4. Speed and velocity can be positive or negative depending upon the direction of motion.

A car travels the first $\dfrac {2}{5}$th part of its total distance with a speed v₁, and the remaining $\dfrac {3}{5}$th of the distance with speed v₂. Its average speed is :

1. $\dfrac{1}{2}\sqrt{\text v$1 \text v2}

2. $\dfrac{\text v$1 +\text v2}{2}

3. $\dfrac{2\text v$1 \text v2}{\text v1 +\text v2}

4. $\dfrac{5\text v$1 \text v2}{3\text v1 +2\text v2}

Write the parameters required to express a scalar quantity.

Name the parameters required to express a vector quantity.