Concepts Of Physics MCQ Edition [Volume 1]PhysicsSome Mechanical Properties of Matter
As a metal wire elongates due to a load suspended from it, the gravitational potential energy decreases.
Options
- AThis energy is shared between the increased elastic potential energy of the wire and heat.
- BThis energy is entirely converted into the increased elastic potential energy of the wire.
- CThis energy is entirely converted into the increased kinetic energy of the block.
- DThis energy is entirely dissipated as heat.
Correct answer
A. This energy is shared between the increased elastic potential energy of the wire and heat.
Step-by-step solution
When a load of mass M is suspended from a metal wire, the wire elongates by a distance x under the constant force F = Mg . The decrease in the gravitational potential energy of the load is U = Mgx . The elastic potential energy stored in the stretched wire is U_ elastic = 1 2 F x = 1 2 Mgx . The remaining energy is U - U_ elastic = Mgx - 1 2 Mgx = 1 2 Mgx . This remaining energy is dissipated as heat. Thus, the decrease in gravitational potential energy is shared between the increased elastic potential energy of th