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

1

The force between the molecules of a liquid in contact with that of a solid is

A

adhesive

B

cohesive

C

magnetic

D

repulsive

**Answer & Comments**

**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

**Answer & Comments**

**correct option:**b

h = \(\frac{p}{eg} = \frac{9100}{2000 \times 10} = 0.455m\)

Users' Answers & Comments3

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

**Answer & Comments**

**correct option:**c

R.d = \(\frac{\text{weight in air}}{\text{apparent loss of weight in water}} = \frac{45}{45 - 15}\)

= \(\frac{45}{30} = 1.50\)

Users' Answers & Comments= \(\frac{45}{30} = 1.50\)

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

**Answer & Comments**

**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

**Answer & Comments**

**correct option:**b

AC = \(\sqrt{8^2 + 6^2}\) = 10km

Distance travelled = 8 + 6 = 14km

Difference = 4 - 10 = 4km

Users' Answers & CommentsDistance 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

\(\frac{mv}{r^2}\)

**Answer & Comments**

**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?

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

**Answer & Comments**

**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}**Answer & Comments**

**correct option:**b

s = \(ut + \frac{1}{2}at^2\)

80 = 0 x 10 + \(\frac{1}{2}\) x a x 10

a = \(\frac{80}{50} = 1.6ms^2\)

Users' Answers & Comments80 = 0 x 10 + \(\frac{1}{2}\) x a x 10

^{2}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

**Answer & Comments**

**correct option:**d

t = \(\sqrt{\frac{2s}{g}} = \sqrt{\frac{2 \times 25}{10}} = 2.24\)

Users' Answers & Comments10

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

**Answer & Comments**

**correct option:**a