JAMB Physics Past Questions & Answers

1,926.

If a cage containing a truck of coal weighing 750 kg is raised to a height of 90 m in a minute, what is the total power expended?
[g = 10 ms2]

11.50 kw

12.60 kw

11.25 kw

12.10 kw

View answer & explanation

Correct answer is C

Power = \(\frac{work done}{time taken}\)

where 1 min = 60s

= \(\frac{mgh}{t}\)
= \(\frac{750 \times 10 \times 90}{60}\)

= 11250w or 11.25kw

1,927.

I. The motion of the tyres of a moving car.
II. The motion of a loaded test tube oscillated
vertically.
III. The beating of the heart.
IV. A stone tied to a string and whirled round.
V. The motion of the pistons in a gasoline engine.
Which of the motions above is simple harmonic?

III, IV and V only

II, III and V only

II, III and IV only

I,II and III only

View answer & explanation

Correct answer is B

Simple harmonic motion is the motion of a body whose acceleration is directed towards a fixed point and is directly proportional to its displacement from point.

Statements ii, iii and v are clear examples

1,928.

A bullet fired vertically upward from a gun held 2.0 m above the ground reaches its maximum height in 4.0s. calculate its initial velocity.

[g = 10ms-2]

10 ms^-1

8 ms^-1

40 ms^-1

20 ms^-1

View answer & explanation

Correct answer is C

At maximum height, the final velocity, v = 0
thus from v = u - gt
0 = u - gt
∴ U = at = 10 x 4 = 40 mls

1,929.

What is the acceleration between two points on a velocity time graph which has coordinates
(10s, 15 ms-1)
and (20 s, 35 ms-1)?

1.7 ms^-2

3.50 ms^-2

1.00 ms^-2

2.00 ms^-2

View answer & explanation

Correct answer is D

Acceleration = \(\frac{ΔV}{Δt}\)

= \(\frac{V - U}{t_2 - t_1}\)

= \(\frac{35 - 15}{20 - 10}\)

= \(\frac{20}{10}\)

= 2ms\(^-2\)

1,930.

I. Diameter of a small ball bearing.
II. Thickness of a pieces of paper.
III. Diameter of a measuring cylinder.
IV. Length of a piece of wire.
Which of the above can be measured using a micrometer screw gauge?

I, II and IV only

I and II only

II and III only

III and IV only

View answer & explanation

Correct answer is B

Of all the instruments used in measuring length,the micrometer screw gauge has the highest reading accuracy (0.01 mm), and is therefore used in measuring very small length such as diameter of a small ball bearing, and thickness of a piece of paper.