# 2005 - WAEC Physics Past Questions and Answers - page 1

1

Which of the following phenomena is the practical evidence for the existence of the continual motion of molecules?

A

Translational motion

B

rotational motion

C

brownian motion

D

oscillatory motion

**correct option:**c

2

Each of the following physical quantities is classified as a vector or a scalar quantity. Which of the classifications is correct?

A

electric potential (Vector)

B

momentum (scalar)

C

gravitational field intensity (scalar)

D

magnetic flux density (vector)

**correct option:**d

3

Which of the following statements about a spring balance and/or a chemical balance is not correct?

A

the chemical balance operates on the principle of moments

B

the sprin balance operates on Hooke's law

C

either may be used to measure the weight of a substance

D

the reading of a spring balance changes over the surface of the earth, while that of the chemical balance remaind constant

**correct option:**c

4

The friction which exists between two layers of liquid in relative motion is called

A

capillarity

B

surface tension

C

viscosity

D

cohension

**correct option:**c

5

A body of mass 25kg, moving at 3ms

^{-1}on a rough horizontal floor is at rest after sliding through a distance of 2.50m on the floor. Calculate the co-efficient of sliding friction. [g = 10.0ms^{-2}]A

0.09

B

0.18

C

0.36

D

0.54

**correct option:**b

a = \(\frac{v^2 - u^2}{2a} = \frac{0^2 - 3^2}{2 \times 2.5}\) = 1.8m/s

F = ma = 25 x 1.8 = 45N

but \(\mu = \frac{F}{R} = \frac{45}{25 \times 10} = 0.18\)

Users' Answers & Comments^{2}F = ma = 25 x 1.8 = 45N

but \(\mu = \frac{F}{R} = \frac{45}{25 \times 10} = 0.18\)

6

Which of the following simple machines is a second class lever?

A

wheel barrow

B

crowbar

C

claw hammer

D

seesae

**correct option:**a

7

A wheel and axle of radii 800mm and 200mm respectively is used to raise a body of weight 800N by the application of 250N. Calculate the efficiency of the machine

A

85%

B

80%

C

60%

D

20%

**correct option:**b

V.R = \(\frac{R}{r} = \frac{800}{200} = 4\)

M.A = \(\frac{L}{E} = \frac{800}{250} = 3.2\)

y = \(\frac{M.A}{v.R} \times \frac{100}{1} = 80\)%

Users' Answers & CommentsM.A = \(\frac{L}{E} = \frac{800}{250} = 3.2\)

y = \(\frac{M.A}{v.R} \times \frac{100}{1} = 80\)%

8

Masses,m

^{1}and m^{2}at the 20-cm and 65-cm marks respectively of a uniform metre rule freely suspended at its centre of gravity. If the metre rule balances horizontally, determine the ratio m^{2}: m^{1}A

2 : 1

B

3 : 3

C

2 : 3

D

1 : 2

**correct option:**d

9

Which of the following type of motion does a body undergo when acted upon by a couple?V

A

vibrational

B

translational

C

rotational

D

random

**correct option:**c

10

A body starts from rest and accelerates uniformly at 5ms

^{-1}until it attains a velocity of 25ms^{-1}. Calculate the time taken to attain this velocityA

2.5s

B

5.0s

C

10.0s

D

125.0s