Scalars and vectors Flashcards – AQA A-level Physics (7408)

What distinguishes a scalar quantity from a vector quantity?

A scalar has magnitude only; a vector has magnitude and direction.

How does an arrow represent a vector?

Its length indicates magnitude, and its orientation indicates direction.

Which three quantities are scalars: speed, mass, distance, velocity, force, weight, acceleration or displacement?

Speed, mass and distance.

Which five quantities are vectors: speed, mass, distance, velocity, force, weight, acceleration or displacement?

Velocity, force, weight, acceleration and displacement.

How do speed and velocity differ?

Speed is the rate at which distance is travelled; velocity is the rate of change of displacement and has a direction.

How do distance and displacement differ?

Distance is the length of a path; displacement is the directed change in position.

What is an object's weight?

The gravitational force on the object.

What does an object's mass measure?

Its inertia.

What is the condition for translational equilibrium?

The vector sum of all forces on the object is zero.

What happens to an object's motion in translational equilibrium?

Its acceleration is zero, so it remains at rest or moves at constant velocity.

What conditions must two forces acting at a point satisfy for equilibrium?

They must be equal in magnitude and opposite in direction.

How are three coplanar forces in equilibrium represented in a head-to-tail force diagram?

As a closed triangle: the final arrow returns to the starting point.

What condition must force components satisfy along two perpendicular axes for equilibrium?

The algebraic sum of the components must be zero along each axis.