# 1995 - JAMB Physics Past Questions & Answers - page 1

1
Which of the following is the dimension of pressure?
A
ML-1T-2
B
MLT-2
C
ML2T-3
D
ML-3
CORRECT OPTION: a
Pressure = heg

= m x $$\frac{kg}{m^3}$$ x $$\frac{m}{5^2}$$

= ML-1T-2
2
The length of a displaced pendulum ball which passes its lowest point twice every seconds is [g = 10m-2]
A
0.25 m
B
0.45 m
C
0.58m
D
1.00m
CORRECT OPTION: a
T = 2$$\pi$$ $$\sqrt\frac{L}{g}$$
T = 2 x 3.142$$\sqrt\frac{L}{10}$$

L= 0.25m
3
When a ball rolls on a smooth level ground, the motion of its center is
A
translational
B
oscillatory
C
random
D
rotational
CORRECT OPTION: a
4
What is the acceleration due to gravity 'g' on the moon, if g is 10-2 on the earth?
A
0. 10 ms-2
B
0.74ms-2
C
1.6ms-2
D
10.00ms-2
CORRECT OPTION: c
s = 10-2 on earth

g = 6 ms-2 on earth

Earth on moon = $$\frac{10}{6}$$

= 1.6ms-2
5
A body is projected from the earth's surface with the intention of letting it escape from the earth's gravitational field. What is the minimum escape velocity of the body? [Earth's radius = 6.4 x 103km, g = 10ms-2]
A
14 kms-1
B
13 kms-1
C
12 kms-1
D
11 kms-1
CORRECT OPTION: d
Velocity = $$\sqrt2gR$$

= 2 x 6400 x 100 x 10

= 11 km-1
6
A uniform rod PQ of length 1m and mass 2kg is pivoted at the end p. If load of 14N is placed at the center of the rod, find the force that should be applied vertically upwards at Q to maintain the rod at equilibrium horizontally [g = 10ms-2]
A
68N
B
28N
C
17N
D
7N
CORRECT OPTION: c
7
A vehicle of mass m is driven by an engine of power P from rest. Find the minimum time it will take to acquire a speed
A
$$\frac{mv^2}{t}$$
B
$$\frac{mv^2}{2t}$$
C
$$\frac{mv}{t}$$
D
$$\frac{mv}{2t}$$
CORRECT OPTION: a
8
Which of the following statements are TRUE about frictional force? i. it is always a disadvantage ii. it is sometimes a disadvantage iii. it always exist where there is a relative motion of two bodies that are in contact iv. it is sometimes very useful
A
i, iii only
B
i, iv only
C
ii, iii only
D
ii, iv only
CORRECT OPTION: d
9
The energy contained in a wire when it extended by 0.02m by a force 500 N is
A
5J
B
10J
C
103J
D
104
CORRECT OPTION: a
Energy = $$\frac{1}{2}$$Fe

= $$\frac{1}{2}$$ x 500 x 0.02

E = 5J
10
A hydraulic press has a large circular piston of radius 0.8m and a circular plunger of radius 0.2m. A force of 500N is exerted by the plunger. Find the force exerted on the piston
A
8000N
B
4000N
C
2000N
D
31N
CORRECT OPTION: d
Pressure on piston = pressure on the plunger

$$\frac{520}{\pi\ \times\ 0.8 \times\ 0.8}$$ = $$\frac{F}{\pi\ \times\ 0.2 \times\ 0.2}$$

F = 31N
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