1.4 Scalars and vectors

Define scalar quantity.

A quantity with magnitude only.

Define vector quantity.

A quantity with both magnitude and direction.

Give one example of a scalar quantity.

Distance, speed, mass, temperature.

Give one example of a vector quantity.

Displacement, velocity, force/weight, acceleration.

State the rule for adding collinear vectors in the same direction.

Add magnitudes: R = A + B.

State the rule for adding collinear vectors in opposite directions.

Subtract magnitudes: R = |A - B|.

State how to find the resultant of two perpendicular vectors.

Use pythagoras: R = √A² + B².

State how to find the resultant of two vectors at an angle θ.

R = √A² + B² + 2AB cosθ.

State how to find the direction of the resultant vector.

tanφ = A sinθ / A + B cosθ.

Describe how to subtract one vector from another.

Reverse the second vector and add it to the first using vector addition rule.