Scalar + vector quantities

Question 1

What are vector quantities?

Answer 1

Vector quantities are physical quantities which have a magnitude + direction.

Question 2

Examples of vector quantities

Answer 2

Force, velocity, displacement, acceleration, momentum, etc

Question 3

What are scalar quantities?

Answer 3

Scalar quantities are physical quantities that have magnitude and no direction.

Question 4

Examples of scalar quantities

Answer 4

Speed, distance, mass, temperature, time, etc

Question 5

How are vectors usually represented + how is this made possible?

Answer 5

Vectors are usually represented by an arrow - the length of the arrow shows the magnitude, and the direction of the arrow shows the direction of the quantity.

Question 6

Why is velocity and speed different + not the same?

Answer 6

Velocity is a vector, but speed is a scalar quantity.

Question 7

How do 2 bikes travelling at the same speed have different velocities?

Answer 7

• 2 bikes are travelling at the same speed (the length of the arrow on a free body diagram would be the same).
• They have different velocities because they are travelling in different directions.

Question 8

How can a force be represented?

Answer 8

Because a force has magnitude + direction, it is a vector quanity + can be represented in a diagram by an arrow.

Question 9

How do free body diagrams work?

Answer 9

Free body diagrams use arrows to show all the forces acting on a single object.
A dot or circle represent the object, with forces drawn as arrows:
* The arrow length represents the magnitude of the force.
* The arrow direction shows the direction of the force.