# 2001 - WAEC Physics Past Questions and 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

radiation of heat

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

Users' Answers & Comments= 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

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

^{-3}m^{3}B

6.4 x 10

^{-3}m^{3}C

3.2 x 10

^{-3}m^{3}D

3.0 x 10

^{-3}m^{3}**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

Users' Answers & Commentsmass(m) = \(\frac{64}{10} = 6.4 kg\)

volume = \(\frac{mass}{Density} = \frac{6.4}{1000}\)

= 6.4 x 10

^{-3}m^{3}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 particleA

0.25ms

^{-2}B

0.50ms

^{-2}C

2.00ms

^{-2}D

5.00ms

^{-2}**correct option:**d

amax = \(\omega^2 r = 10^2 \times \frac{5}{100} = 5ms^{-2}\)

Users' Answers & Comments10

The time rate of change of momentum is

A

impulse

B

force

C

power

D

pressure

**correct option:**b