# 2013 - JAMB Physics Past Questions & Answers - page 1

1
When a brick is taken from the earth's surface to the moon, its mass
A
remains constant
B
reduces
C
increases
D
becomes zero
CORRECT OPTION: a
2
The resultant of two forces is 50N. If the forces are perpendicular to each other and one of them makes an angle 0f 30o with the resultant, find its magnitude.
A
100.0N
B
57.7N
C
43.3N
D
25.0N
CORRECT OPTION: c
F = 50Cos30o = 43.3
3
The pair of physical quantities that are scalar only are ?
A
volume and area
B
moment and momentum
C
length and displacement
D
Impulse and time
CORRECT OPTION: a
This is because volume and the area have only magnitude but no direction
4
A simple pendulum of length 0.4m has a period of 2s. What is the period a similar pendulum of length 0.8m at the same place?
A
8s
B
4s
C
2$$\sqrt{2}s$$
D
$$\sqrt{2}s$$
CORRECT OPTION: c
T2 = $$\sqrt{\frac{L^2 \times T_1^2}{L_1}}$$

= $$\sqrt{\frac{0.8 \times 2^2}{0.4}}$$

= 2$$\sqrt{2}s$$
5
A train with an initial velocity of 20ms-1 is subjected to a uniform deceleration of 2m-2. The time required to bring the train to a complete halt is?
A
5s
B
10s
C
20s
D
40s
CORRECT OPTION: b
t = $$\frac{v - u}{a}$$ = $$\frac{0 - 20}{-2}$$ = 10s
6
Calculate the apparent weight loss of a man weighing 70kg in an elevator moving downwards with an acceleration of 1.5ms-2.

[g = 10ms-2]
A
686N
B
595N
C
581N
D
105N
CORRECT OPTION: d
Wt loss = mg - m (g - a)

= 70 x 10 - 70 (10 - 1.5) = 105N
7
A piece of cork floats in a liquid. What fraction of its volume will be immersed in the liquid?

[Density of the cork = 0.25 x 103kgm-3, Density of the liquid = 1.25 x 103kgm-3]
A
0.8
B
0.5
C
0.2
D
0.1
CORRECT OPTION: c
$$\frac{0.25 \times 10^3} {1.25 \times 10^3}$$ = 0.2
8
An object is moving with a velocity of 5m-1. At what height must a similar body be situated to have a potential energy equal in value with kinetic energy of the moving body?
A
25.0m
B
20.0m
C
1.3m
D
1.0m
CORRECT OPTION: c
P.E = K.E

Therefore, h = $$\frac{v^2}{2g} = \frac{5^2}{2 \times 10}$$

= 1.25

Approx 1.3 (C)
9
If a pump is capable of lifting 5000kg of water through a vertical height of 60m in 15 min, the power of the pump is
A
2.2.5 x 10 5js-1
B
2.5 x 104js-1
C
3.3 x 103js-1
D
3.3 x 102js-1
CORRECT OPTION: c
P = $$\frac{mgh}{t}$$

P = $$\frac{5000 \times 10 \times 60}{(15 \times 60)s}$$

P = 3333.3333

P = 3.3 x 103js-1
10
The coefficient of friction between two perfectly smooth surface is
A
infinity
B
one
C
half
D
zero
CORRECT OPTION: d
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