WAEC Physics Past Questions & Answers - Page 29

141.

A ball of mass 0.5kg moving at 10ms\(^{-1}\) collides with another ball of equal mass at rest. If the two balls move off together after the impact, calculate their common velocity.

A.

0.2ms\(^{-1}\)

B.

0.5ms\(^{-1}\)

C.

5.0ms\(^{-1}\)

D.

5.5ms\(^{-1}\)

Correct answer is C

Using; m\(_{1}\) u\(_{1}\) + m\(_{2}\) u\(_{2}\) = (m\(_{1}\) + m\(_{2}\))v

m\(_{1}\) = 0.5kg, u\(_{1}\) = 10ms\(^{1}\), m\(_{2}\) = 0.5kg, u\(_{1}\) = 0

\(\therefore\) (0.5kg x 10) + (0.5 x 0) = (0.5 + 0.5)v

v = 5ms\(^{1}\)

142.

Which of the units of the following physical quantities are derived?

I. Area
II. Thrust
III. Pressure
IV. Mass

A.

I, II, III and IV

B.

I, II, and III only

C.

I, II, and IV only

D.

I and IV only

Correct answer is B

Only 'mass' is a fundamental quantity 

143.

A man will exert the greatest pressure when he?

A.

lies flat on his back

B.

lies on his belly

C.

stands on both feet

D.

stands on the toes of one foot

Correct answer is D

Pressure varies inversely as A

i.e P \(\propto\) \(\frac{1}{A}\)

144.

The slope of the straight line displacement-time graph indicates?

A.

distance traveled

B.

uniform velocity

C.

uniform acceleration

D.

uniform speed

Correct answer is B

\(\frac{\bigtriangleup s}{\bigtriangleup t}\) = uniform velocity

145.

Which of the following statement about viscosity is not true? it

A.

depends on areas of the surfaces in contact

B.

occurs in fluids

C.

is independent of the relative velocity of the layers

D.

depends on the tangential force between the layers

Correct answer is A

No explanation has been provided for this answer.