B.
y− 3 − 2 − 1 0 1 2 3 4 x152520105− 5− 10y = 2 x^2 − 3 x − 2
> 0 for
x > 2 and x < −^123.3.3 Formulae
(i) Ohm’s law;V=voltage,I=current,R=resistance.Vis a linear function ofR–in
fact it is proportional toR.R=V
I(ii) Electrical powerP, resistanceR, currentI.Pis proportional toR.R=P
I^2(iii) Kinetic EnergyE,m=mass,v=velocity.Eis a quadratic function ofv.
v=±√
2 E
m(iv) Distance – time function;s=distance,t=time,u=initial velocity,a=acceleration.
sis a quadratic function oft.
t=−u±√
u^2 + 2 as
a(v) Einstein’s mass – energy formula;E=energy,m=mass,c=speed of light (posi-
tive!).Eis proportional toc^2.c=√
E
m