Elastic strain energyAQA A-Level Physics: Mind map

Exam questions on Elastic strain energy

1. A spring obeys Hooke's law within its limit of proportionality. A force of 8.0 N extends the spring by 0.040 m.
   Calculate the additional energy that must be transferred to the spring to increase its extension from 0.040 m to 0.080 m.2 marks
2. A technician loads a steel wire with increasing weights until it has been stretched beyond its elastic limit, and then removes the weights one by one. After unloading, the wire is found to be permanently longer than at the start and feels slightly warm.
   Explain, in terms of energy, why the wire is slightly warm after it has been unloaded.2 marks
3. A pinball machine launches a steel ball of mass 0.080 kg using a spring of spring constant 320 N m⁻¹. The spring is compressed by 0.045 m and then released. The ball leaves the spring when the spring reaches its natural length. Take g = 9.81 m s⁻².
   Calculate the speed of the ball as it leaves the spring, assuming the spring energy is transferred entirely to the kinetic energy of the ball.3 marks