# Practice Test: Question Set - 12

**1. A ball of mass 250 g moving on a smooth horizontal table with a velocity of 10 m/sec hits an identical stationary ball ‘**

*B’*on the table. If the impact is perfectly plastic, the velocity of the ball ‘*B’*just after impact would be- (A) Zero

- (B) 5 m/sec

- (C) 10
m/sec

- (D) None
of these

**2. The length of a Second's pendulum, is**

- (A) 99.0 cm

- (B) 99.4 cm

- (C) 100 cm

- (D) 101 cm

**3. The following statement is one of the laws of Dynamic friction**

- (A) The
force of friction always acts in a direction opposite to that in which a body
is moving

- (B) The
magnitude of the kinetic friction bears a constant ratio to the normal reaction
between two surfaces. The ratio being slightly less than that in the case of
limiting friction

- (C) For
moderate speeds the force of friction remains constant but decreases slightly
with the increase of speed

- (D) All the
above

**4. Force polygon method is applicable for**

- (A) Any coplanar force system

- (B) A system of parallel forces only

- (C) Concurrent coplanar force system

- (D) Non-concurrent coplanar force system

**5. A weight of 100 kg is supported by a string whose ends are attached to pegs ‘**

*A’*and ‘*B’*at the same level shown in below figure. The tension in the string is- (A) 50 kg

- (B) 750 kg

- (C) 100 kg

- (D) 120 kg

**6. A particle moves along a straight line such that distance ‘**

*x’*traversed in ‘*t’*seconds is given by*x*=*t*^{2}(*t*+ 1), the acceleration of the particle, will be- (A) 3

*t*

^{3}- 2

*t*

- (B) 3

*t*

^{2}+ 2

*t*

- (C) 6

*t*- 2

- (D) 6

*t*+ 2

**7. If two forces**

*P*and*Q*(*P*>*Q*) act on the same straight line but in opposite direction, their resultant, is- (A)

*P*+

*Q*

- (B)

*P*/

*Q*

- (C)

*Q*/

*P*

- (D)

*P*-

*Q*

**8. The condition of equilibrium for any system of forces in a plane is**

- (A) That polygon of forces must close

- (B) That resultant couple must be zero

- (C) Both (A) and (B)

- (D) None of the above

**9. Varingon’s theorem of moment’s states**

- (A) Arithmetical
sum of the moments of two forces about any point, is equal to the moments of
their resultant about that point

- (B) Algebraic
sum of the moments of two forces about any point, is equal to the moment of
their resultant about that point

- (C) Arithmetical
sum of the moments of the forces about any point in their plane, is equal to
the moment of their resultant about that point

- (D) Algebraic
sum of the moments of the forces about any point in their plane, is equal to
the moment of their resultant about that point

**10. If**

*g*_{1}and*g*_{2}are**the gravitational**

**accelerations on two mountains**

*A*and*B*respectively,**the weight of a body when transported from**

*A*to*B*will be multiplied by- (A)

*g*

_{1}

- (B)

*g*

_{2}

- (C)

*g*

*/*

_{1}*g*

_{2}- (D)

*g*

*/*

_{2}*g*

_{1}**11. The characteristic of a couple is:**

- (A) Algebraic
sum of forces, constituting a couple is zero

- (B) Algebraic
sum of moments of forces, constituting a couple, about any point, is same

- (C) A couple can
be never the balanced by a single force

- (D) All
the above

**12. When two forces, each equal to**

*P*, act at 90° to each other, then the resultant will be- (A)

*P*

- (B)

*P*√2

- (C)

*P*/√2

- (D) 2

*P*

**13. The displacement of a particle which moves along a straight line is given by**

*S*= 4*t*^{3}+ 3*t*^{2}- 10 where ‘*S’*is in meters and*t*is in seconds. The time taken by the particle to acquire a velocity of 18 m/sec from rest, is- (A) ½ sec

- (B) 1 sec

- (C) 1.2 sec

- (D) 1.5 sec

**14. Which one of the following statements is true?**

- (A) The tangent
of the angle of friction is equal to coefficient of friction

- (B) The angle of
repose is equal to angle of friction

- (C) The tangent
of the angle of repose is equal to coefficient of friction

- (D) All
the above

**15. A load of 500 kg was lifted through a distance of 13 cm. by an effort of 25 kg which moved through a distance of 650 cm. The velocity ratio of the lifting machine is**

- (A) 50

- (B) 55

- (C) 60

- (D) 65

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