2004 - JAMB Physics Past Questions and Answers - page 2
11
In a hydraulic press , a force of 40N is applied on the effort piston of area 0.4m2. If the force exerted on the load piston is 400N, the area of the large piston is
A
4m2
B
8m2
C
2m2
D
1m2
correct option: a
Pressure developed in the effort piston = F/a
∴F/a = 40/0.4 = 400/4 = 100Nm2
this pressure is transmitted to the larger piston of area A; => P = F/A
∴ 100 = 400/A
=> A = 400/100 = 4m2
Users' Answers & Comments∴F/a = 40/0.4 = 400/4 = 100Nm2
this pressure is transmitted to the larger piston of area A; => P = F/A
∴ 100 = 400/A
=> A = 400/100 = 4m2
12
A 100kg box is pushed along a road with force of 500N. If the box moves with a uniform velocity, the coefficient of friction between the box and the road is
A
0.4
B
1.0
C
0.8
D
0.5
correct option: d
Coefficient of friction μ = F/R = F/mg = 500/1000 = 0.5
∴ μ = 0.5
Users' Answers & Comments∴ μ = 0.5
13
As the pressure of a fluid increases, its viscosity
A
decreases
B
increases
C
increases then decreases
D
remains constant
correct option: b
Users' Answers & Comments14
A
13N
B
17N
C
√3N
D
7√3N
correct option: a
Component of 8N along the horizontal = 8 cos 60o = 8 x 0.5
= 4N
Similarity Component of 6N along the horizontal = 6 cos 60o = 3N
∴ Total force towards the right = 10 + 4 + 3
= 17N
Again total force toward the left = 4N
∴ Net horizontal force (towards the right) = 17-4
= 13N
Users' Answers & Comments= 4N
Similarity Component of 6N along the horizontal = 6 cos 60o = 3N
∴ Total force towards the right = 10 + 4 + 3
= 17N
Again total force toward the left = 4N
∴ Net horizontal force (towards the right) = 17-4
= 13N
15
The earth is four times the size of the moon and the acceleration due to gravity on the earth is 80 times that on the moon. The ratio of the mass of the moon to that of the earth is
A
1:80
B
1:320
C
1:1280
D
1:4
correct option: a
NOTE: Firstly, it should be noted that the mass, as well as the weight of a body is independent of its size.
∴ Let the weight of the moon = Mm x gm
weight of the earth = Me x ge
But ge = 80gm
∴ weight of the earth = Me x 80gm
=> weight of the moon / weight of the earth = Mm x gm / Me x 80gm
thus Mm/Me ∝ gm/80gm ∝ 1/80
=> Mm:Me ∝ 1:80
Users' Answers & Comments∴ Let the weight of the moon = Mm x gm
weight of the earth = Me x ge
But ge = 80gm
∴ weight of the earth = Me x 80gm
=> weight of the moon / weight of the earth = Mm x gm / Me x 80gm
thus Mm/Me ∝ gm/80gm ∝ 1/80
=> Mm:Me ∝ 1:80
16
In which of the following material media will sound travel fastest?
A
oil
B
metal
C
gas
D
water
correct option: b
Users' Answers & Comments17
What types of mirror are capable of producing parallel beams of light such as those arising from the headlamps of a car?
A
Parabolic mirrors
B
Plane mirrors
C
Cylindrical mirrors
D
Spherical mirrors
correct option: a
Users' Answers & Comments18
What happens to the rays in a parallel beam of light?
A
They diverge as they travel
B
they intersect
C
They converge as they travel
D
They meet at infinity.
correct option: d
Users' Answers & Comments19
A ray of light makes an angle of 35o with a plane mirror. What is the angle of reflection?
A
35o
B
55o
C
70o
D
65o
20
A person can focus an object only when it lies within 200cm from him. Which spectacles should be used to increase his maximum distance of distinct vision infinity
A
Convex lens
B
Binoculars
C
Concave lens
D
Plane glasses
correct option: c
Users' Answers & Comments