WAEC Physics Past Questions & Answers - Page 221

1,101.

In which of the points labelled A, B, C, D and E on the conductor shown would electric charge tend to concentrate most?

A.

A

B.

B

C.

C

D.

D

E.

E

Correct answer is E

No explanation has been provided for this answer.

1,102.

Two objects of masses 80kg and 50kg are separated by a distance of 0.2m. If the gravitational constant is 6.6 x 10-11Nm kg, calculate the gravitational attraction between them.

A.

4.9 x 10-9N

B.

1.3 x 10-6N

C.

6.6 x 10-8N

D.

6.6 x 10-6N

E.

2.6 x 10-9N

Correct answer is D

F = \(\frac{Gm_1m_2}{r^2} = \frac{6.6 \times 10^{-11} \times 80 \times 50}{0.2 \times 0.2}\)

= 6.6 x 10-6N

1,103.

A force of 500N1 is applied to a steel wire of cross-sectional area 0.2m2, The tensile stress is

A.

2.5x104Nm-2

B.

1.0x102Nm-2

C.

1.0x103Nm-2

D.

2.5x103Nm-2

Correct answer is D

\(Stress = \frac{Force}{Area}\)

\(Stress = \frac{500}{0.2} = 2500\)

= 2.5 x 103Nm-3

1,105.

What happens when three coplanar non-parallel forces are in equilibrium?

A.

Their lines of action are parallel.

B.

They are represented in magnitude only

C.

They are represented in direction only

D.

Their lines of action meet at a point

Correct answer is D

Conditions for non-parallel coplanar forces