44 CHAPTER 1. PROPERTIES OF MATTER
- Draw a representative stress-strain diagram of a brittle material.
- Draw a representative stress-strain diagram of a ductile material.
- List a set of information about a material that you can extract its stress-strain
diagram. - Define Young’s Modulus. What is its unit?
- Define Rigidity Modulus. What is its unit?
- Define Bulk Modulus. What is its unit?
- Define Poisson’s ratio.
- When a compressed string is dissolved in acid what happens to the elastic
potential energy of the string [ 8 ]? - When a wire is repeatedly bent back and forth it becomes hot. Why?
- When a block of mass is suspended by a long wire of lengthL, the elastic
potential energy stored in the wire is^12 ◊stress◊strain◊volume. Show that
it is equal to^12 Mgl, wherelis the extension. The loss in gravitational potential
energy of mass-earth system isMgl. Where does the remaining^12 Mglgo [ 8 ]? - List the factors that a ect elastic modulus and tensile strength of materials.
- How do temperature changes and presence of impurities a ect elastic properties
of materials? - How do hammering and rolling a ect elastic properties of materials?
- What is meant by (a) neutral surface and (b) neutral axis of a beam.
- How are the various filaments of a beam a ected when the beam is loaded?
- Distinguish between uniform bending and non-uniform bending.
- What are I- shape girders?
- State the advantages and limitations of I-shaped girders.
Part B (16 marks) - Questions for detailed Answers (25 to 28 minutes to answer each)
- Derive an expression for the torsional couple per unit angular twist when a
cylinder is twisted. - Derive an expression for the period of oscillation of a torsional pendulum. How
can it be used to determine the torsional rigidity (Rigidity Modulus) of a wire? - What is meant by bending moment of a beam? Derive the expression for the
bending moment of a beam. - Derive the expression for the depression at the free end of a cantilever due
to load. Describe an experiment to determine the young’s modulus of the
cantilever using this expression. - Explain, with necessary theory, the method of determination of young’s mod-
ulus of elasticity of the material of a beam supported at its ends and loaded in
the middle (non-uniform bending). - Explain, with necessary theory, the method of determination of young’s mod-
ulus of elasticity of the material of a beam supported symmetrically on two
knife edges and loaded equally at its ends (uniform bending).