THE EFFECTS OF FORCES ON MATERIALS 17
exceeded, the force that will stretch the
wire 5 mm is:
(a) 150 N (b) 250 N
(c) 90 N (d) 450 N
- For the wire in question 4, the extension
when the applied force is 450 N is:
(a) 1 mm (b) 3 mm
(c) 9 mm (d) 12 mm
- Due to the forces acting, a horizontal
beam is in:
(a) tension (b) compression
(c) shear
- Due to forces acting, a pillar supporting
a bridge is in:
(a) tension (b) compression
(c) shear
- Which of the following statements is
false?
(a) Elasticity is the ability of a material
to return to its original dimensions
after deformation by a load.
(b) Plasticity is the ability of a material
to retain any deformation produced
in it by a load.
(c) Ductility is the ability to be perma-
nently stretched without fracturing.
(d) Brittleness is the lack of ductility
and a brittle material has a long
plastic stage.
- A circular rod of cross-sectional area
100 mm^2 has a tensile force of 100 kN
applied to it. The stress in the rod is:
(a) 1 MPa (b) 1 GPa
(c) 1 kPa (d) 100 MPa
- A metal bar 5.0 m long extends by
0.05 mm when a tensile load is applied
to it. The percentage strain is:
(a) 0.1 (b) 0.01
(c) 0.001 (d) 0.0001
An aluminium rod of length 1.0 m and
cross-sectional area 500 mm^2 is used to
support a load of 5 kN which causes the
rod to contract by 100μm. For questions
11 to 13, select the correct answer from
the following list:
(a) 100 MPa (b) 0.001 (c) 10 kPa
(d) 100 GPa (e) 0.01 (f) 10 MPa
(g) 10 GPa (h) 0.0001 (i) 10 Pa
- The stress in the rod
- The strain in the rod
- Young’s modulus of elasticity
- A compound bar of lengthLis subjected
to a temperature rise ofT.Ifα 1 >α 2 ,
the strain in bar 1 will be:
(a) tensile (b) compressive
(c) zero (d)αT
- For Problem 14, the stress in bar 2
will be:
(a) tensile (b) compressive
(c) zero (d)αT
