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Materials

Q1. A sample of wire has a Young modulus E. When a force F is applied to it it extends by 10 mm

A second sample of wire made from an identical material has three times the length and half the diameter of the first sample.

What is the extension of the second wire if a force F is applied ot it?

A
2.5 mm
B
10 mm
C
60 mm
D
120 mm

 

Q2. A sample of wire has a Young modulus E.

A second sample of wire made from an identical material has three times the length and half the diameter of the first sample.

What is the Young modulus of the second sample of wire in terms of E?

A
0.25E
B
E
C
6E
D
12E

 

Q3. What is the name given to a material that breaks without deformation when a force is applied to it?

A
Plastic
B
Brittle
C
Stiff
D
Elastic

 

Q4. What cannot be used as a unit for the Young modulus?

A
N m–2
B
Pa
C
kg m–2 s–2
D
kg m–1 s–2

 

Q5. Two separate wires X and Y have the same original length and cross-sectional area.

The sketch graph above shows the extension ΔL produced in X and Y when the tensile force F applied to the wires is increased up to the point where they break.

Which statement is incorrect?

A
For a given extension more energy is stored in X than in Y.
B
The Young modulus of the material of wire Y is greater than that of wire X.
C
Both wire X and wire Y obey Hooke’s law.
D
Wire X has a greater breaking stress than wire Y.