# 2001 - WAEC Physics Past Questions & Answers - page 1

1
Which of the following physical processes cannot be explained by the molecular theory of matter?
A
evaporation
B
thermal conduction
C
D
convectional current of fliuds
CORRECT OPTION: c
2
A spring balance,which is suspended from the roof of a lift, carries a mass of 1kg at its free end. If the lift accelerates upwards at 2.5ms-2, determine the reading on the spring balance. [g = 10ms-2]
A
24.0N
B
12.5N
C
7.5N
D
4.0N
CORRECT OPTION: b
F = ma

= 1 x 2.5 = 2.5N

weight = mg = 1 x 10 = 10N

Reading = F + Wt = 2.5 + 10

= 12.5N
3
An object weight 10N immersed in a liquid displaces a quantity of the liquid. If the liquid displaced weighs 6N, determine the upthrust of the object
A
20N
B
10N
C
6N
D
4N
CORRECT OPTION: c
Upthrust = Weight of fluid displayed = 6N
4
Which of the following statements about pressure is not correct? pressure
A
increases with an increase in surface area
B
decreases with an increase in surface area
C
increases with a decrease in surface area
D
increases with an increase in the applied force
CORRECT OPTION: a
5
The apparent weight of a body fully immersed in water is 32N and its weight in air is 96N. Calculate the volume of the body. [Density of water = 1000kgm-3, g = 10ms-2]
A
8.9 x 10-3m3
B
6.4 x 10-3m3
C
3.2 x 10-3m3
D
3.0 x 10-3m3
CORRECT OPTION: b
Upthrust = 96 - 32 = 64N

mass(m) = $$\frac{64}{10} = 6.4 kg$$

volume = $$\frac{mass}{Density} = \frac{6.4}{1000}$$

= 6.4 x 10-3m3
6
A block weighing 15N rests on a flat surface and a horizontal force of 3N is exerted on it. Determine the friction force on the block
A
0.3N
B
0.5N
C
3.0N
D
5.0N
CORRECT OPTION: c
7
Which of the following equations represents the distance x, travelled by a body moving on a straight road with a constant speed? [The other symbol have their usual meanings]
A
x = Ut + $$\frac{1}{2}t^2$$
B
x = Ut
C
x = $$\frac{V^2 - U^2}{2a}$$
D
x = -$$\frac{1}{2} at^2$$
CORRECT OPTION: b
8
The amplitude of the motion of a body performing simple harmonic motion decreases with time because
A
friction force dissipate the energy of motion
B
the frequency of oscillation varies with time
C
the period of oscillation varies with time
D
energy is supplied by some external agency
CORRECT OPTION: b
9
The amplitude of a particle executing simple harmonic motion in 5cm while its angular frequency is 10 rad s-1. calculate the magnitude of the maximum acceleration of the particle
A
0.25ms-2
B
0.50ms-2
C
2.00ms-2
D
5.00ms-2
CORRECT OPTION: d
amax = $$\omega^2 r = 10^2 \times \frac{5}{100} = 5ms^{-2}$$
10
The time rate of change of momentum is
A
impulse
B
force
C
power
D
pressure
CORRECT OPTION: b
Pages: