# Basic Mechanical Engineering Questions On Engineering Mechanics And Strength Of Materials

• What is Strain energy??
• What is the difference between Stress and Pressure?
• What is Truss?
• Types of truss:
• A vertical column has two moments of inertia (i.e. Ixx and Iyy). The column will tend to buckle in the direction of the___________
• What is neutral axis?
• What is Poisson’s ratio?
• Can Poisson Ratio be Negative or zero?
• Poisson’s Ratio is higher in, Rubber/Steel/Wood?
• What is Poisson effect?

Q: What is Strain energy??
Ans.: Strain energy is the energy stored in a body when strained within elastic limits.

Q: What is the difference between
Ans.:
Pressure=Force/Area. And Stress=Resistive force/Area.
Pressure represent intensity of external forces acting at a point. But stress represent intensity of internal resisting forces develop at a point.

Q: What is Truss?
Ans.: Truss is a rigid structure composed of number of straight members pin jointed to each other.
It can sustain dynamic and static load without any relative motion to each other.

Q: Types of truss:
Ans.:
Plain truss
Rigid truss
Simple truss.

Q. A vertical column has two moments of inertia (i.e. Ixx and Iyy ). The column will tend to buckle in the direction of the___________
Ans.: minimum moment of inertia.

Q: What is neutral axis?
Ans.: The neutral axis of the cross-section a beam is that axis at which the bending stress is zero.

Q: What is Poisson’s ratio?
Ans.: Poisson’s ratio is the ratio of lateral strain to longitudinal strain.
Its value is always less than one. Poisson ratio is often represented by 1/m or μ

Q: Can Poisson Ratio be Negative or zero?
Ans.: Poisson’s ratio for a cork is almost zero. Yes Poisson’s ratio can be negative. Such materials are called as “auxetics”. E.g. Human ligaments

Q. Poisson’s Ratio is higher in, Rubber/Steel/Wood?
Ans.:
For rubber = 0.5
For steel = 0.288
For wood < 0.2
Thus Poisson’s ratio is higher in RUBBER.

Q: What is Poisson effect?

Ans.: When a material is compressed in one direction, it usually tends to expand in the other two directions perpendicular to the direction of compression. This phenomenon is called the Poisson effect. Poisson’s ratio is a measure of the Poisson effect.