1994 - JAMB Physics Past Questions & Answers - page 1

1
If it takes 5.0 hrs to drain a container of 540.0cm3 of water, what is the flow rate of water from the container in kg-1? [Density of water = 1000kgm-3]
A
32.5kg-1 s
B
31.5kg-1
C
[]
D
[]
CORRECT OPTION: d
2
A boat travels due east at a speed 40ms-1s across a river flow due south at 30ms-1s. What is the resultant speed of the boat?
A
1.3ms-1
B
10.0ms-1
C
50.0ms-1
D
70.0ms-1
CORRECT OPTION: c
3
An object is projected with a velocity of 80ms-1 at an angle of 30o to the horizontal.The maximum height reached is
A
20m
B
80m
C
160m
D
320m
CORRECT OPTION: b
max. height = \(\frac{U^2\sin^2\theta}{2g}\)

= \(\frac{80 \times 80 \times \sin^2(30)}{2 \times 10}\)

= 80m
4
A motor vehicle is brought to rest from a speed of 15ms-1 in 20 seconds. Calculate the retardation.
A
0.75ms-1
B
1.33ms-2
C
5.00ms-2
D
7.50ms-2
CORRECT OPTION: a
Retardation = \(\frac{u - v}{t}\)

= \(\frac{15 -0}{20}\)

= 0.75ms-1
5
Which of the following is TRUE of a particle moving in a horizontal circle with constant angular velocity?
A
The energy is costant but the linear momentum varies
B
The linear momentum is conatant but the energy varies
C
both energy and linear momentum are constant
D
The speed and the linear velocity are both constant
CORRECT OPTION: c
6
An object of mass 50kg is released from a height of 2m.Find the kinetic energy just before it strikes the ground
A
250J
B
1000J
C
10 000J
D
100 000J
CORRECT OPTION: b
P.E = K.E = mgh

= 50 x 10 x 2 = 1000J
7
A cone in an unstable equilibrium has its potential energy
A
decreased
B
increased
C
unchanged
D
oscillating
CORRECT OPTION: b
8
Calculate the magnitude of the force required to just move a 20kg object along a horizontal surface if the coefficient of friction is 0.2. [g = 10ms-2]
A
400.0N
B
40.0N
C
4.0N
D
0.4N
CORRECT OPTION: b
F = \(\mu\)mg

= 0.2 x 20 x 10

= 40N
9
Calculate the velocity ratio of a screw jack of pitch 0.3cm if the length of the tommy bar is 21cm
A
\(\frac{1}{140}\)\(\pi\)
B
14\(\pi\)
C
70\(\pi\)
D
140\(\pi\)
CORRECT OPTION: d
V.R = \(\frac{2\pi L}{p}\)

= \(\frac{2 \times \pi \times 2}{0.3}\)

V.R = 140\(\pi\)
10
A force of 15N stretches a spring to a total length of 30cm. An additional force of 10N stretches the spring 5cm further. Find the natural length of the spring
A
25.0cm
B
22.5cm
C
20.0cm
D
15.0cm
CORRECT OPTION: b
\(\frac{15}{30 - L}\) = \(\frac{10}{5}\)

L = 22.5cm
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