# 1989 - WAEC Physics Past Questions & Answers - page 1

1
Which of the following is NOT a vector quantity?
A
momentum
B
force
C
velocity
D
temperature
CORRECT OPTION: d
2
Which of the following is not a consequence of a force field?
A
wieght
B
surface tension
C
gravitational pull
D
magnetic force
CORRECT OPTION: b
3
A boy pulls a nail from the wall with a string tied to the nail. The string is inclined at an angle of 60o to the wall. If the tension in the string is 4N, what is the effective force used in pulling the nail?
A
2√3 N
B
4 N
C
4√3 N
D
8 N
CORRECT OPTION: a
F = 4 x sin 60o
F = 4 x √3/2 = 2√3 N
4
Which of the following is used to determine the relative density of the acid in a car battery?
A
Hypsometer
B
Hygrometer
C
Manometer
D
Hydrometer
CORRECT OPTION: d
5
A block of material of volume 20cm-3 and density 2.5gcm-3 is suspended from a spring balance with half the volume immersed in water. What is the reading of the spring balance? (Density of water = 1.0gcm-3).
A
8g
B
25g
C
30g
D
40g
CORRECT OPTION: d
W = pvg = (2.5 x 10 x 60)/100 = 0.500N.
Upthrust = wt of liquid displaced = pvg water.
pvg water = (1x20x10)/2 = 0.10N
Reading => 0.500N - 0.100N = 0.4N = 40g
6
A piece of cork floating on water is acted upon by the forces of...
A
Weight and viscosity
B
weight and upthrust
C
upthrust and viscosity
D
weight only
CORRECT OPTION: b
7
A stone tied to a string is made to revolve in a horizontal circle of radius 4m with an angular speed of 2 rad per sec. With what tangential velocity will the stone move off the circle if the string is cut?
A
16.0 ms-1
B
8.0 ms-1
C
6.0 ms-1
D
2.0 ms-1
CORRECT OPTION: b
V = wr = 2x4 = 8.0 ms-1
8
The motion of the prongs of the sounding tuning fork is
A
random
B
translational
C
rotational
D
vibratory
CORRECT OPTION: d
9
Which of the following is a derived unit?
A
Metre
B
Coulomb
C
Kilogram
D
Second
CORRECT OPTION: b
10
An engine raises 1000kg of water through a height of 60m in 20s. What is the power of the engine? (Take g = 10ms-2>).
A
120,000 W
B
30,000 W
C
333 W
D
300 W
CORRECT OPTION: b
P = mgh/t = (1000 $$\times$$ 10 $$\times$$ 60) $$\div$$ 20 = 30,000 W.
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