JAMB Physics Past Questions & Answers - Page 334

1,666.

A ball is moving at 18ms-1 in a direction inclined at 60o to the horizontal. The horizontal component to its velocity is

A.

9√3ms-1 ·

B.

6√3ms-1 ·

C.

8√3ms-1 ·

D.

9ms-1 ·

Correct answer is D

No explanation has been provided for this answer.

1,667.

The physical quantity that has the same dimensions as impulse is

A.

energy

B.

momentum

C.

surface tension

D.

pressure

Correct answer is B

Impulse = F x t = m(v-u)

1,668.

The velocity of a sound wave at 27oC is 360ms-1. Its velocity at 127oC is

A.

120√3 ms-1

B.

240 ms-1

C.

240√3 ms-1

D.

720√3 ms-1

Correct answer is C

Velocity \(\alpha \sqrt{temperature}\)

\(\frac{V_1}{V_2} = \sqrt{\frac{T_1}{T_2}}\)

therefore, \(\frac{360}{V_2} = \sqrt{\frac{27 + 273}{127 + 273}}\)

\(V_2 = 240\sqrt{3}\)m/s

1,669.

A bullet fired at a wooden block of thickness 0.15m manages to penetrate the block. If the mass of the bullet is 0.025kg and the average resisting force of the wood is 7.5 x 103N, calculate the speed of the bullet just before it hits the wooden block.

A.

450ms-1

B.

400ms-1

C.

300ms-1

D.

250ms-1

Correct answer is C

F = ma

Therefore, a = \(\frac{F}{m}\)

a = \(\frac{7.5 \times 10^{3}}{0.025}\)

a = 3 x 105m/s2

using V2 = U2 + 2ax;

V2 = 02 + (2 x 3 x 105 x 0.15)

Therefore V = 300 m/s

1,670.

I. Small size.
II. Low power requirement
III. Not easily damaged by high temperature
IV. Highly durable.

Which of the above are the advantages of semiconductors?

A.

I,II and lll only

B.

ll,lll and lV only

C.

l, II and lV only

D.

l, ll, lll and lV

Correct answer is C

No explanation has been provided for this answer.