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}

State whether the following quantity is a scalar or vector?

(a) Pressure

(b) Force

(c) Momentum

(d) Energy

(e) Weight

(f) Speed

Name the parameters required to express a vector quantity.

What does the negative sign with a vector quantity indicates?