# Practice Test: Question Set - 07

**1. Two bodies of masses**

*m*_{1}and*m*_{2}are hung from the ends of a rope, passing over a frictionless pulley as shown in the figure below. The acceleration of the string will be- (A)

*g (m*

_{1}- m_{2})/(m_{1}+ m_{2})- (B) 2

*g (m*

_{1}- m_{2})/(m_{1}+ m_{2})- (C)

*g (m*

_{1}+ m_{2})/(m_{1}- m_{2})- (D) 2

*g (m*

_{1}+ m_{2})/(m_{1}- m_{2})**2. The velocity ratio of a differential wheel and axle with '**

*D'*as the diameter of effort wheel and*d*_{1}and*d*_{2}as the diameters of larger and smaller axles respectively, is- (A)

*D/(d₁ + d₂)*

- (B)

*D/(d₁ - d₂)*

- (C) 2

*D/(d₁ + d₂)*

- (D) 2

*D/(d₁ - d₂)*

**3. Which of the following is not the unit of power?**

- (A) kW (kilowatt)

- (B) hp (horse power)

- (C) kcal/sec

- (D) kcal/kg sec

**4. Non-coplanar non-concurrent forces are those forces which**

- (A) Meet
at one point, but their lines of action do not lie on the same plane

- (B) Do
not meet at one point and their lines of action do not lie on the same plane

- (C) Do
not meet at one point but their lines of action lie on the same plane

- (D) None
of the above

**5. The unit of force in S.I. units is**

- (A) kilogram

- (B) Newton

- (C) Watt

- (D) Dyne

**6. A number of forces acting at a point will be in equilibrium, if**

- (A) All
the forces are equally inclined

- (B) Sum of all
the forces is zero

- (C) Sum of
resolved parts in the vertical direction is zero (i.e. ∑

*V*= 0)

- (D) None
of these

**7. The weight of a body is due to**

- (A) Gravitational pull
exerted by the earth

- (B) Forces experienced by
body in atmosphere

- (C) Force of attraction
experienced by particles

- (D) Gravitational force
of attraction towards the centre of the earth

**8. The efficiency of a lifting machine is the ratio of**

- (A) Output
to the input

- (B) Work
done by the machine to the work done on the machine

- (C) Mechanical
advantage to the velocity ratio

- (D) All
of the above

**9. According to principle of moments**

- (A) If a system of
coplanar forces is in equilibrium, then their algebraic sum is zero

- (B) If a system of coplanar forces is in
equilibrium, then the algebraic sum of their moments about any point in their
plane is zero

- (C) The algebraic sum of
the moments of any two forces about any point is equal to moment of the
resultant about the same point

- (D) Positive and negative
couples can be balanced

**10. Moment of inertia of a triangular section of base (**

*b*) and height (*h*) about an axis passing through its vertex and parallel to the base, is __________ than that passing through its C.G. and parallel to the base.- (A) Nine
times

- (B) Six
times

- (C) Four times

- (D) Two
times

**11. A trolley wire weighs 1.2 kg per meter length. The ends of the wire are attached to two poles 20 meters apart. If the horizontal tension is 1500 kg find the dip in the middle of the span**

- (A) 2.5 cm

- (B) 3.0 cm

- (C) 4.0 cm

- (D) 5.0 cm

**12. The algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This is known as**

- (A) Principle
of independence of forces

- (B) Principle
of resolution of forces

- (C) Principle
of transmissibility of forces

- (D) None
of these

**13. A particle moves along a straight line such that distance (x) traversed in**

*'t'*seconds is given by x =*t²*(*t*- 4), the acceleration of the particle will be given by the equation- (A) 6

*t²*- 8

*t*

- (B) 3

*t²*+ 2

*t*

- (C) 6

*f*- 8

- (D) 6

*f*- 4

**14. The minimum force required to slide a body of weight '**

*W'*on a rough horizontal plane is- (A)

*W*

*sinθ*

- (B)

*W cosθ*

- (C)

*W tanθ*

- (D) None
of these

**15. The maximum frictional force which comes into play when a body just begins to slide over another surface is called**

- (A) Limiting friction

- (B) Sliding friction

- (C) Rolling friction

- (D) Kinematic friction

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