2.2 Using expressions and formulae
SUBSTITUTING INTO FORMULAS
Find the value of the variable by substituting the given values into the formula.
Newton’s 2nd law of motion
Volume of a pyramid
1
× area of base × height
3
1
V = Ah
3
Force = mass × acceleration
Volume =
F = ma
Find F when m = 5 and a = 300
Find V when A = 270 and h = 5
F = ma
V=
= ____ × ____
=
1
Ah
3
1
× ____ × ____
3
= ________
= ____ × ____
= ________
Distance travelled
Coulomb’s law
Distance travelled using starting velocity, time
and acceleration
Electrostatic interaction between electrical
particles
s = ut +
1 2
at
2
Find s when u = 8, t = 3 and a = –4
s = ut +
F= k
q 1q 2
r2
Find F when k = 5, q1 = 4, q2 = 50 and r = 10
1 2
at
2
= ____ × ____ +
1
× ____ × ____2
2
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Chapter 2: Expressions, formulae and equations