Question 1
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 ?
0.25E
E
6E
12E
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Question 2
Two vertical copper wires X and Y of equal length are joined as shown. Y has a greater diameter than X. A weight W is hung from the lower end of Y.
Which of the following is correct?
the strain in X is the same as that in Y
the stress in Y is greater than that in X
the tension in Y is the same as that in X
the elastic energy stored in X is less than that stored in Y
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Question 3
Two wires X and Y have the same extension for the same load.
X has a diameter d and is made of a metal of density ρ and Young modulus E.
Y has the same mass and length as X but its diameter is 2d.
What are the density and the Young modulus of the metal from which Y is made?
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Question 4
An experiment is carried out to determine the Young modulus E of steel using a vertical wire of initial length L and cross-sectional area A. Various weights are suspended from the wire. A graph of extension against weight is plotted.
What does the gradient of the graph represent?
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Question 5
Which quantities can be written in the fundamental units kg m–1 s–2?
tensile stress and kinetic energy
the moment of a force and kinetic energy
young modulus and the moment of a force
young modulus and tensile stress
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Question 6
A tensile force produces an extension ∆L in a steel wire of initial length L and diameter d.
The same steel is used to make a second wire of initial length 2L and diameter .
What is the extension when the same force is applied to the second wire?
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Question 7
A load of 50 N is suspended from a wire that has an area of cross-section of 1 mm2.
The stress in the wire, in Pa, is between
100 and 103
103 and 106
106 and 109
109 and 1012
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Question 8
What is the name given to a material that breaks without deformation when a force is applied to it?
plastic
brittle
stiff
elastic
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Question 9
What cannot be used as a unit for the Young modulus?
N m–2
pa
kg m–2 s–2
kg m–1 s–2
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Question 10
The force F against extension x graphs for four different wires A, B, C and D up to their breaking points are shown below.
Which wire has the greatest work done on it before it breaks?
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