Higher November 2020 Paper 2R Q20

EdexcelHigherCurrent spec4 marksDirect & Inverse Proportion

20 \(T\) is inversely proportional to \(m^2\)
\(T = 30\) when \(m = 0.5\)

(a) Find a formula for \(T\) in terms of \(m\). (3)

(b) Work out the value of \(T\) when \(m = 0.1\) (1)

Mark scheme (a)

Scheme	Marks
\(T = \dfrac{k}{m^2}\) or \(Tm^2 = k\)	M1
\(30 \times 0.5^2 = k\) or \(30 = \dfrac{k}{0.5^2}\) or \(k = 7.5\) or \(k = \dfrac{15}{2}\)	M1
\(T = \dfrac{7.5}{m^2}\)	A1
	(3)

M1: for a correct equation with a constant
Do not allow constant = 1

M1: dep on M1 for correct substitution in a correct equation

M2 for \(k = 7.5\) or \(k = \dfrac{15}{2}\)

A1: for \(T = \dfrac{7.5}{m^2}\) or \(T = \dfrac{15}{2m^2}\)

SCB2 for \(Tm^2 = 7.5\) or \(Tm^2 = \dfrac{15}{2}\)

or \(m^2 = \dfrac{7.5}{T}\) or \(m^2 = \dfrac{15}{2T}\)