1

Which of the following physical processes cannot be explained by the molecular theory of matter?

A

evaporation

B

thermal conduction

C

radiation of heat

D

convectional current of fliuds

CORRECT OPTION:
c

2

A spring balance,which is suspended from the roof of a lift, carries a mass of 1kg at its free end. If the lift accelerates upwards at 2.5ms^{-2}, determine the reading on the spring balance. [g = 10ms^{-2}]

A

24.0N

B

12.5N

C

7.5N

D

4.0N

CORRECT OPTION:
b

F = ma

= 1 x 2.5 = 2.5N

weight = mg = 1 x 10 = 10N

Reading = F + Wt = 2.5 + 10

= 12.5N

= 1 x 2.5 = 2.5N

weight = mg = 1 x 10 = 10N

Reading = F + Wt = 2.5 + 10

= 12.5N

3

An object weight 10N immersed in a liquid displaces a quantity of the liquid. If the liquid displaced weighs 6N, determine the upthrust of the object

A

20N

B

10N

C

6N

D

4N

CORRECT OPTION:
c

Upthrust = Weight of fluid displayed = 6N

4

Which of the following statements about pressure is not correct? pressure

A

increases with an increase in surface area

B

decreases with an increase in surface area

C

increases with a decrease in surface area

D

increases with an increase in the applied force

CORRECT OPTION:
a

5

The apparent weight of a body fully immersed in water is 32N and its weight in air is 96N. Calculate the volume of the body. [Density of water = 1000kgm^{-3}, g = 10ms^{-2}]

A

8.9 x 10^{-3}m^{3}

B

6.4 x 10^{-3}m^{3}

C

3.2 x 10^{-3}m^{3}

D

3.0 x 10^{-3}m^{3}

CORRECT OPTION:
b

Upthrust = 96 - 32 = 64N

mass(m) = \(\frac{64}{10} = 6.4 kg\)

volume = \(\frac{mass}{Density} = \frac{6.4}{1000}\)

= 6.4 x 10^{-3}m^{3}

mass(m) = \(\frac{64}{10} = 6.4 kg\)

volume = \(\frac{mass}{Density} = \frac{6.4}{1000}\)

= 6.4 x 10

6

A block weighing 15N rests on a flat surface and a horizontal force of 3N is exerted on it. Determine the friction force on the block

A

0.3N

B

0.5N

C

3.0N

D

5.0N

CORRECT OPTION:
c

7

Which of the following equations represents the distance x, travelled by a body moving on a straight road with a constant speed? [The other symbol have their usual meanings]

A

x = Ut + \(\frac{1}{2}t^2\)

B

x = Ut

C

x = \(\frac{V^2 - U^2}{2a}\)

D

x = -\(\frac{1}{2} at^2\)

CORRECT OPTION:
b

8

The amplitude of the motion of a body performing simple harmonic motion decreases with time because

A

friction force dissipate the energy of motion

B

the frequency of oscillation varies with time

C

the period of oscillation varies with time

D

energy is supplied by some external agency

CORRECT OPTION:
b

9

The amplitude of a particle executing simple harmonic motion in 5cm while its angular frequency is 10 rad s^{-1}. calculate the magnitude of the maximum acceleration of the particle

A

0.25ms^{-2}

B

0.50ms^{-2}

C

2.00ms^{-2}

D

5.00ms^{-2}

CORRECT OPTION:
d

amax = \(\omega^2 r = 10^2 \times \frac{5}{100} = 5ms^{-2}\)

10

The time rate of change of momentum is

A

impulse

B

force

C

power

D

pressure

CORRECT OPTION:
b

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