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} s

B

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 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

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

= 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}

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

= 0.75ms

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

= 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

= 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\(\pi\)

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

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

L = 22.5cm

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