7.1 - Vectors and scalars

Question 1

what is a vector

Answer 1

a physical property that has a magnitude and given direction

Question 2

what is a scalar

Answer 2

a physical quantity that only has a magnitude

Question 3

define displacement

Answer 3

distance in a given (straight) direction

Question 4

define velocity

Answer 4

speed in a given direction

Question 5

how are vectors represented in diagrams

(3)

Answer 5

as straight arrows

length is proportional to the size of the vector (using scale ratio)

the direction of arrows is also the same as the direction of the actual vector

Question 6

when are vectors added

• which direction does the resultant force go

Answer 6

when they are acting in the same direction on the same line

• resultant vector moves in the same direction as the forces

Question 7

when are vectors subtracted

• which direction does the resultant force go

Answer 7

when they are acting in the opposite, on the same line

• resultant vector moves in the same direction as the larger force

Question 8

what is important to do when using diagrams to calc resultant force

(4)

Answer 8

• rearrange arrows tip to tail
• draw the largest diagram possible
• state a scale ratio

(draw and measure length of Resultant force x scale to get magnitude )

• state s direction of the missing force

(angle from a given force line - measured using a protractor)

Question 9

what is important to do when using calculations to calc resultant force

(3)

Answer 9

• redraw diagram tip to tail
• calc the magnitude using Pythagoras
• calc angles using tan = o/a

(rearranging angle from a given force)

Question 10

what can be calculated from a result force

Answer 10

its 2 perpendicular vector forces

Question 11

how to calculate the vector components of a resultant force

Answer 11

• Use trig to calc lengths of the vector components
• state the angle fro the resultant force the forces are from too