MEDIUM
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A wire is stretched under a force. If the wire suddenly snaps the temperature of the wire

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Important Questions on Elasticity

MEDIUM
The elastic limit of brass is 379 MPa. The minimum diameter of a brass rod if it is to support a 400 N load without exceeding its elastic limit will be
EASY
Young’s moduli of the material of wires A and B are in the ratio of 1 : 4, while its area of cross sections are in the ratio of 1 : 3. If the same amount of load is applied to both the wires, the amount of elongation produced in the wires A and B will be in the ratio of [Assume length of wires A and B are same]
MEDIUM
The Young's modulus of steel is twice that of brass. Two wires of same length and of same area of cross-section, one of steel and another of brass are suspended from the same roof. If we want the lower ends of the wires to be at the same level, then the weights added to the steel and brass wires must be in the ratio of:
EASY
A fixed volume of iron is drawn into a wire of length L. The extension x produced in the wire by a constant force F is proportional to _____.
MEDIUM
A load of mass M kg is suspended from a steel wire of length 2 m and radius 1.0 mm in Searle's apparatus experiment. The increase in length produced in the wire is 4.0 mm. Now the load is fully immersed in a liquid of relative density 2. The relative density of the material of load is 8. The new value of increase in length of the steel wire is:
HARD

Calculate the strain energy per unit volume in a brass wire of length 3 m and area of cross-section 0.6 mm2 when it is stretched by 3 mm and a force of 6 kg wt is applied to its free end.

MEDIUM
A metal rod of length L and cross-sectional area A is heated through T °C. What is the force required to prevent the expansion of the rod lengthwise?
[Y = Young's modulus of the material of rod, α= coefficient of linear expansion]
EASY
Which one of the following is most elastic in nature?
MEDIUM
Two wires of the same material and length but cross sectional area in the ratio 1:2 are used to suspend the same loads. The extension in them will be in the ratio
MEDIUM
A particle of mass 1 kg is moving in SHM with a path length of 0.01 m and frequency of 50 Hz. The maximum force in newton, acting on the particle is
EASY
A wire of diameter 1 mm breaks under a tension of 1000 N. Another wire of the same material as that of the first one, but of diameter 2 mm breaks under a tension of:
EASY
A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his density remains same, the stress in the leg will change by a factor of:
HARD
A pendulum made of a uniform wire of cross sectional area A has time period T. When an additional mass M is added to its bob, the time period changes to TM . If the Young's modulus of the material of the wire is Y, then 1Y is equal to:
(g=gravitational acceleration)
HARD
An external pressure P is applied on a cube at 0°C so that it is equally compressed from all sides. K is the bulk modulus of the material of the cube and α is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by:
MEDIUM
A steel rail of length 5 m and area of cross section 40 cm2 is prevented from expanding along its length while the temperature rises by 10°C . If coefficient of linear expansion and Young's modulus of steel are 1.2×10-5  K-1 and 2×1011 N m-2 respectively, the force developed in the rail is approximately:
EASY
One end of a horizontal thick copper wire of length 2L and radius 2R is welded to an end of another horizontal thin copper wire of length L and radius R. When the arrangement stretched by applying forces at two ends, the ratio of the elongation in the thin wire to that in the thick wire is 
HARD
In plotting stress versus strain curves for two materials P and Q , a student by mistake puts strain on the y -axis and stress on the x - axis as shown in the figure. Then the correct statement(s) is(are)

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HARD
A steel wire is suspended vertically from a rigid support. When the wire is loaded with a weight in air, it is extended by xa. When the weight is completely inside the water, the extension becomes xw. The relative density of the material of the weight is,
EASY
Breaking stress of a steel wire is p and the density of steel is ρ. The greatest length of steel wire that can hang vertically without breaking is