1

Which of the following phenomena is the practical evidence for the existence of the continual motion of molecules?

A

Translational motion

B

rotational motion

C

brownian motion

D

oscillatory motion

CORRECT OPTION:
c

2

Each of the following physical quantities is classified as a vector or a scalar quantity. Which of the classifications is correct?

A

electric potential (Vector)

B

momentum (scalar)

C

gravitational field intensity (scalar)

D

magnetic flux density (vector)

CORRECT OPTION:
d

3

Which of the following statements about a spring balance and/or a chemical balance is not correct?

A

the chemical balance operates on the principle of moments

B

the sprin balance operates on Hooke's law

C

either may be used to measure the weight of a substance

D

the reading of a spring balance changes over the surface of the earth, while that of the chemical balance remaind constant

CORRECT OPTION:
c

4

The friction which exists between two layers of liquid in relative motion is called

A

capillarity

B

surface tension

C

viscosity

D

cohension

CORRECT OPTION:
c

5

A body of mass 25kg, moving at 3ms^{-1} on a rough horizontal floor is at rest after sliding through a distance of 2.50m on the floor. Calculate the co-efficient of sliding friction. [g = 10.0ms^{-2}]

A

0.09

B

0.18

C

0.36

D

0.54

CORRECT OPTION:
b

a = \(\frac{v^2 - u^2}{2a} = \frac{0^2 - 3^2}{2 \times 2.5}\) = 1.8m/s^{2}

F = ma = 25 x 1.8 = 45N

but \(\mu = \frac{F}{R} = \frac{45}{25 \times 10} = 0.18\)

F = ma = 25 x 1.8 = 45N

but \(\mu = \frac{F}{R} = \frac{45}{25 \times 10} = 0.18\)

6

Which of the following simple machines is a second class lever?

A

wheel barrow

B

crowbar

C

claw hammer

D

seesae

CORRECT OPTION:
a

7

A wheel and axle of radii 800mm and 200mm respectively is used to raise a body of weight 800N by the application of 250N. Calculate the efficiency of the machine

A

85%

B

80%

C

60%

D

20%

CORRECT OPTION:
b

V.R = \(\frac{R}{r} = \frac{800}{200} = 4\)

M.A = \(\frac{L}{E} = \frac{800}{250} = 3.2\)

y = \(\frac{M.A}{v.R} \times \frac{100}{1} = 80\)%

M.A = \(\frac{L}{E} = \frac{800}{250} = 3.2\)

y = \(\frac{M.A}{v.R} \times \frac{100}{1} = 80\)%

8

Masses,m^{1} and m^{2} at the 20-cm and 65-cm marks respectively of a uniform metre rule freely suspended at its centre of gravity. If the metre rule balances horizontally, determine the ratio m^{2} : m^{1}

A

2 : 1

B

3 : 3

C

2 : 3

D

1 : 2

CORRECT OPTION:
d

9

Which of the following type of motion does a body undergo when acted upon by a couple?V

A

vibrational

B

translational

C

rotational

D

random

CORRECT OPTION:
c

10

A body starts from rest and accelerates uniformly at 5ms^{-1} until it attains a velocity of 25ms^{-1}. Calculate the time taken to attain this velocity

A

2.5s

B

5.0s

C

10.0s

D

125.0s

CORRECT OPTION:
b

V = u + at = 25 = 0 + 5t

t = 5s

t = 5s

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