JAMB Physics Past Questions & Answers - Page 222

1,107.

The linear expansivity of brass is 2 x 10-5 oC-1. If the volume of a piece of brass is 10cm3 at 0oC, what will be its volume at 100oC?

A.

10.02cm3

B.

10.04cm3

C.

10.06cm3

D.

10.20cm3

E.

102.00cm3

Correct answer is C

3 x \(\alpha\) = \(\frac{V_2 - V_1}{\Delta \theta \times V_1}\)

3 x 2 x 10-5 = \(\frac{V_2 - 10}{10 \times 100}\)

V2 = 10.06cm3

1,108.

A man of mass 50kg ascends a flight of stairs 5m high in 5 seconds. If acceleration due to gravity is 10ms-2, the power expended is?

A.

100W

B.

200W

C.

250W

D.

400W

E.

500W

Correct answer is E

Power = \(\frac{\text{force x distance}}{\text{time}}\)

= \(\frac{50 × 10 × 5}{5}\)= 500W

1,110.

A train has an initial velocity of 44ms-1 and an acceleration of -4ms-1. Its velocity after 10 seconds is

A.

2ms-1

B.

4ms-1

C.

8ms-1

D.

12ms-1

E.

16ms-1

Correct answer is B

Using V = at + u

V = (-4 x 10) + 44

= 4ms-1