1

When a brick is taken from the earth's surface to the moon, its mass

A

remains constant

B

reduces

C

increases

D

becomes zero

CORRECT OPTION:
a

2

The resultant of two forces is 50N. If the forces are perpendicular to each other and one of them makes an angle 0f 30^{o} with the resultant, find its magnitude.

A

100.0N

B

57.7N

C

43.3N

D

25.0N

CORRECT OPTION:
c

F = 50Cos30^{o} = 43.3

3

The pair of physical quantities that are scalar only are ?

A

volume and area

B

moment and momentum

C

length and displacement

D

Impulse and time

CORRECT OPTION:
a

This is because volume and the area have only magnitude but no direction

4

A simple pendulum of length 0.4m has a period of 2s. What is the period a similar pendulum of length 0.8m at the same place?

A

8s

B

4s

C

2\(\sqrt{2}s\)

D

\(\sqrt{2}s\)

CORRECT OPTION:
c

T_{2} = \(\sqrt{\frac{L^2 \times T_1^2}{L_1}}\)

= \(\sqrt{\frac{0.8 \times 2^2}{0.4}}\)

= 2\(\sqrt{2}s\)

= \(\sqrt{\frac{0.8 \times 2^2}{0.4}}\)

= 2\(\sqrt{2}s\)

5

A train with an initial velocity of 20ms^{-1} is subjected to a uniform deceleration of 2m^{-2}. The time required to bring the train to a complete halt is?

A

5s

B

10s

C

20s

D

40s

CORRECT OPTION:
b

t = \(\frac{v - u}{a}\) = \(\frac{0 - 20}{-2}\) = 10s

6

Calculate the apparent weight loss of a man weighing 70kg in an elevator moving downwards with an acceleration of 1.5ms^{-2}.

[g = 10ms^{-2}]

[g = 10ms

A

686N

B

595N

C

581N

D

105N

CORRECT OPTION:
d

Wt loss = mg - m (g - a)

= 70 x 10 - 70 (10 - 1.5) = 105N

= 70 x 10 - 70 (10 - 1.5) = 105N

7

A piece of cork floats in a liquid. What fraction of its volume will be immersed in the liquid?

[Density of the cork = 0.25 x 10^{3}kgm^{-3}, Density of the liquid = 1.25 x 10^{3}kgm^{-3}]

[Density of the cork = 0.25 x 10

A

0.8

B

0.5

C

0.2

D

0.1

CORRECT OPTION:
c

\(\frac{0.25 \times 10^3} {1.25 \times 10^3}\) = 0.2

8

An object is moving with a velocity of 5m^{-1}. At what height must a similar body be situated to have a potential energy equal in value with kinetic energy of the moving body?

A

25.0m

B

20.0m

C

1.3m

D

1.0m

CORRECT OPTION:
c

P.E = K.E

Therefore, h = \(\frac{v^2}{2g} = \frac{5^2}{2 \times 10}\)

= 1.25

Approx 1.3 (C)

Therefore, h = \(\frac{v^2}{2g} = \frac{5^2}{2 \times 10}\)

= 1.25

Approx 1.3 (C)

9

If a pump is capable of lifting 5000kg of water through a vertical height of 60m in 15 min, the power of the pump is

A

2.2.5 x 10 ^{5}js^{-1}

B

2.5 x 10^{4}js^{-1}

C

3.3 x 10^{3}js^{-1}

D

3.3 x 10^{2}js^{-1}

CORRECT OPTION:
c

P = \(\frac{mgh}{t}\)

P = \(\frac{5000 \times 10 \times 60}{(15 \times 60)s}\)

P = 3333.3333

P = 3.3 x 10^{3}js^{-1}

P = \(\frac{5000 \times 10 \times 60}{(15 \times 60)s}\)

P = 3333.3333

P = 3.3 x 10

10

The coefficient of friction between two perfectly smooth surface is

A

infinity

B

one

C

half

D

zero

CORRECT OPTION:
d

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