# 1994 - JAMB Physics Past Questions and Answers - page 1

1

If it takes 5.0 hrs to drain a container of 540.0cm

^{3}of water, what is the flow rate of water from the container in kg^{-1}? [Density of water = 1000kgm^{-3}]A

32.5kg

^{-1}sB

31.5kg

^{-1}C

[]

D

[]

**correct option:**d

2

A boat travels due east at a speed 40ms

^{-1}s across a river flow due south at 30ms^{-1}s. 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 30^{o}to the horizontal.The maximum height reached isA

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

Users' Answers & Comments= \(\frac{80 \times 80 \times \sin^2(30)}{2 \times 10}\)

= 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

Users' Answers & Comments= \(\frac{15 -0}{20}\)

= 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

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

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\(\pi\)

Users' Answers & Comments= \(\frac{2 \times \pi \times 2}{0.3}\)

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