4.1 Scalars and Vectors

Question 1

what is a scalar quantity?

Answer 1

a quantity with a magnitude but no direction

Question 2

what is a vector quantity?

Answer 2

a quantity with a magnitude and a direction

Question 3

what are examples of scalar quantities?

Answer 3

length/distance, speed, mass, temperature, time, energy

Question 4

what are examples of vector quantities?

Answer 4

displacement, velocity, force (including weight), acceleration, momentum

Question 5

how do you find the resultant vector using scale diagrams?

Answer 5

• draw the vectors to scale
• draw them ‘tip to tail’
• measure the length and angle of the line connecting the tip to the tail

Question 6

how do you find the resultant vector using trigonometry?

Answer 6

if the vectors are perpendicular to each other (90 degrees) you can:
- calculate the size of the resultant vector R using the formula: R^2 = a^2 + b^2
- calculate the size of the angle by using the formula: angle = tan^-1(b/a)

Question 7

how do you find the horizontal component of a vector?

Answer 7

Vh = v x cosθ

Question 8

how do you find the vertical component of a vector?

Answer 8

Vv = v x sinθ