(I am going to publish a question bank for EME-102/EME-202 of 1st yr.
MTU; Greater Noida. Some pages from the book .......Subhankar Karmakar)

**1)**

**Explain the principle of Super-position.**

Ans: The principle of superposition states
that “The effect of a force on a body does not change and remains same if we
add or subtract any system which is in equilibrium.”

In the fig 4 a, a force P is applied at
point A in a beam, where as in the fig 4 b, force P is applied at point A and a
force system in equilibrium which is added at point B. Principle of super
position says that both will produce the same effect.

**2)**

**What is “Force-Couple system?”**

Ans: When a force is required to transfer
from a point A to point B, we can transfer the force directly without changing
its magnitude and direction but along with the moment of force about point B.

As a result of parallel transfer a system is obtained which is always a
combination of a force and a moment or couple. This system consists of a force
and a couple at a point is known as Force-Couple system.

In fig 5 a, a force P acts on a bar at point
A, now at point B we introduce a system of forces in equilibrium (fig 5 b),
hence according to principle of superposition there is no change in effect of
the original system. Now we can reduce the downward force P at point A and
upward force P at point B as a couple of magnitude Pxd at point B (fig 5 c).

**3) What do you understand by Equivalent force systems?**

Ans: Two different force systems will be
equivalent if they can be reduced to the same force-couple system at a given
point. So, we can say that two force systems acting on the same rigid body will
be equivalent if the sums of forces or resultant and sums of the moments about
a point are equal.

**4)**

**What is orthogonal or perpendicular resolution of a force?**

Ans: The resolution of a force into
two components which are mutually perpendicular to each other along X-axis and
Y-axis is called orthogonal resolution of a force.

If a force F acts on an object at an angle θ with the
positive X-axis, then its component along X-axis is

**F**, and that along Y-axis is_{x}= Fcosθ**F**_{y}= Fsinθ**5) What is oblique or non-perpendicular resolution of a force?**

Ans: When a force is required to be resolved
in to two directions which are not perpendiculars to each other the resolution
is called oblique or Non-perpendicular resolution of a force.

**F**_{OA}= (P sin β)/ sin (α +β)**F**

_{OB}= (P sin α**)/ sin (α +β)**

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