Answer:
a) M = 504
b) r = ±8
Explanation:
Given that M is directly proportional to r²
Expressing this mathematically, we get
M ∝ r²
or M = k r², where K is a constant
we are given that r = 2 when M = 14, substitute these into the formula
M = kr²
14 = k (2)²
14 = k (4)
k = 14/4 = 3.5
hence our formula becomes M = 3.5 r²
a) when r = 12, M = 3.5 (12)² = 504
b) when M = 224
224 = 3.5 r²
r² = 224/3.5 = 64
r = √64
r = ±8