Chap 21 - ratio, rate, proportions

Question 1

2 ways to find ratios & increase/ decrease them

Answer 1

-cross multiply
-unitary method

Question 2

how to find scales in form of 1:n & n:1

Answer 2

-make same units
-make dimensions same
-divide
map/ irl = map/ irl or irl/ map = irl/ map

Question 3

distance time graph

Answer 3

-moving forward - up linear
-stationary - flat line
-back to original/ opp. direction - down line
-gradient = speed
-total distance = count the lines

Question 4

speed time graph

Answer 4

-acceleration - up linear
-constant speed - flat line
-negative acceleration - down line
-gradient = acceleration
-total distance = are under graph

Question 5

formula for speed

Answer 5

speed = distance/ time

Question 6

formula for acceleration

Answer 6

a = (final velocity - initial velocity)/ time

Question 7

how to go from m/min to km/ h

Answer 7

120 x 15
———— = 1.8/ 1
4 x 14

Question 8

direct proportions graph

Answer 8

-linear from origin
-y = mx + c, c = 0

Question 9

formula for direct propotions

Answer 9

y = kx
k = constant
x up, y up
x down, y down

Question 10

indirect proportions graph

Answer 10

y = k/x
k = constant
x up, y down
x down, y up