# 2002 - WAEC Physics Past Questions & Answers - page 1

1
The force between the molecules of a liquid in contact with that of a solid is
A
B
cohesive
C
magnetic
D
repulsive
CORRECT OPTION: a
2
A reservoir is filled with a liquid of density 2000kgm-3. Calculate the depth at which the pressure in the liquid will equal to 9100Nm-2 [g = 10ms-2]
A
0.262m
B
0.455m
C
0.664m
D
0.819m
CORRECT OPTION: b
h = $$\frac{p}{eg} = \frac{9100}{2000 \times 10} = 0.455m$$
3
A solid weight 45N and 15N respectively in air and water. Determine the relative density of the solid
A
0.33
B
0.50
C
1.50
D
3.00
CORRECT OPTION: c
R.d = $$\frac{\text{weight in air}}{\text{apparent loss of weight in water}} = \frac{45}{45 - 15}$$

= $$\frac{45}{30} = 1.50$$
4
One common characteristics of solids, liquids and gasses is that
A
all the three has fixed volume
B
their molecule have the same size
C
their molecules are always in motion
D
all the three have the same inter molecular forces
CORRECT OPTION: b
5
A boy travels 8 km eastward to a point B and then 6km northward to another point C. Determine the difference between the magnitude of displacement of the boy and distance travelled by him
A
2.0km
B
4.0km
C
10.0km
D
13.0km
CORRECT OPTION: b
AC = $$\sqrt{8^2 + 6^2}$$ = 10km

Distance travelled = 8 + 6 = 14km

Difference = 4 - 10 = 4km
6
The magnitude of the force required to make an object of mass, m move with speed, v in a circular of radius r is given by the expression
A
$$\frac{mr}{v}$$
B
$$\frac{mr^2}{v}$$
C
$$\frac{mv^2}{r}$$
D
$$\frac{mv}{r^2}$$
CORRECT OPTION: c
7
A man was moving round a circular path continuously for 4 minutes and covered the following distances in the times stated :
Distance (in metres) 200, 400, 600, 300
Time(in minutes) : 1, 2, 3, 4 respectively. Which of the following statements is correct about the motion of the man?
A
the man was moving without uniform velocity
B
the speed was changing constantly
C
the velocity was uniform
D
it was an instance of motion in which both speed and velocity are the same
CORRECT OPTION: c
8
A car takes off from rest and covers a distance of 80m on a straight road in 10s. Calculate the magnitude of its acceleration
A
1.25ms-2
B
1.60ms-2
C
4.00ms-2
D
8.00ms-2
CORRECT OPTION: b
s = $$ut + \frac{1}{2}at^2$$

80 = 0 x 10 + $$\frac{1}{2}$$ x a x 102

a = $$\frac{80}{50} = 1.6ms^2$$
9
An object is released from rest at a height of 25m. Calculate the time it takes to fall to the ground. [g = 10ms-2]
A
25.00s
B
10.00s
C
2.50s
D
2.24s
CORRECT OPTION: d
t = $$\sqrt{\frac{2s}{g}} = \sqrt{\frac{2 \times 25}{10}} = 2.24$$
10
An object is acted upon by a system of parallel forces causing the object to be in static equilibrium. Which of the following statements is not correct?
A
The resultant of the parallel force is zero
B
the algebraic sum of the moment of the forces is zero
C
all the parallel forces must be equal in magnitude and in direction
D
the sum of the forces in one direction must be equal to the sum of forces in the opposite direction
CORRECT OPTION: a
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