Elastic Potential Energy

IMPORTANT

Elastic Potential Energy: Overview

This topic covers concepts, such as, Potential Energy of a Stretched Wire, Work Done by Spring Force & Elastic Potential Energy etc.

Important Questions on Elastic Potential Energy

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IMPORTANT

An aluminium rod with Young’s modulus Y=7.0 ×1010 N m-2 undergoes elastic strain of 0.04%. The energy per unit volume stored in the rod in SI unit

MEDIUM
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A force of 10 N holds an ideal spring with a 20 N/m spring constant in compression. The potential energy stored in the spring is 

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A wire loaded by a load Mg extends by l, mechanical energy stored in the wire is,

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A wire of length 'L' suspended vertically from a rigid support is made to suffer extension 'l' in its length by applying a force 'F'. Then the work done is           

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When a 8 m long wire is stretched by a load of 10 kg.wt, it is elongated by 1.5 mm. The energy stored in the wire in this process is _____g=10 m·s-2

MEDIUM
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A rod elongates by l when a body of mass M is suspended from it. The work done is

HARD
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K is the force constant of a spring. The work done in increasing its extension from l1 to l2 will be

HARD
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A work of2×102 J is done on a wire of length 50 cm and area of cross-section 0.5 mm2. If the Young's modulus of the material of the wire is 2×1010 N m2, then the wire must be

HARD
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When a steel wire fixed at one end is pulled by a constant force F at its other end, its length increases by l. Which of the following statements is not correct?

EASY
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K is the force constant of a spring. The work done in increasing its extension from l1 to l2 will be

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The ratio of elastic potential energy per unit volume for two wires made out of same material and having same length but diameter in the ratio 1:2, when stretched by the same load is:

EASY
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An ideal initially unstretched spring with spring constant k is hung from the ceiling with a block of mass M attached to its lower end. The maximum possible extension in the spring when the mass is released is ___

HARD
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Lengths L, 2L and 3L and radii R, 2R and 3R of three wires of the same material (Young's modulus Y), respectively which are joined end to end with weight w is suspended as shown below. Find the elastic potential energy of the system neglecting the self-weight.

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A catapult is made of rubber cord which is 42 cm long, with 6 m m diameter of cross-section and of negligble mass. The boy keeps a stone weighing 0.02 kg on it and stretches the cord by 20 cm by applying a constant force. When released, the stone flies off with a velocity of 20ms-1. Neglect the change in the area of crose-section of the cord while stretched. The Young's modulus of rubber is approx:

EASY
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Two springs P and Q having stiffness constants K1 and K2(<K1) respectively, are stretched equally. Then:

EASY
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When the load on a wire is increased from 3 kg wt to 5 kg wt the elongation increases from 0.61 mm to 1.02 mm. The required work done during the extension of the wire is

MEDIUM
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An elastic string of length 42 cm  and cross section area 10-4 m2 is attached between two pegs at a distance of 6 mm. A particle of mass 50 g is kept at mid point of string and stretched by 20 cm and released. As string attains natural length, the particle attains a speed 20m/s . Then young’s modulus of string is of order

MEDIUM
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Initially, a block of mass m is at rest on a frictionless floor and the spring is in a relaxed condition. One end of the spring is rigidly attached to the block and the other end is fixed to a wall. A constant force is applied on the block as shown in the figure. The maximum velocity of the block is

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MEDIUM
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Work done for a certain spring when stretched through 1 mm is 10 joule. The amount of work that must be done on the spring to stretch it further by 1 mm is

MEDIUM
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One end of a slack wire (Young's modulus, Y, length, L and cross-sectional area, A) is clamped to a rigid wall and the other end to a block (mass m) which rests on a smooth horizontal plane. The block is set in motion with a speed, v. What is the maximum distance the block will travel after the wire becomes taut?