Elastic strain energyEdexcel A-Level Physics: Flashcards
What these 12 flashcards ask
- What does the area under a force–extension graph represent?
- Give the equation for elastic strain energy of a material obeying Hooke's law.
- Why is there a factor ½ in Eel = ½Fx?
- A spring has F = 15 N at x = 0.060 m. What energy is stored?
- What happens to the stored energy if the extension of a Hooke's law spring is doubled?
- How do you find the energy stored when the graph is a curve?
- What is the area of one trapezium strip of width h?
- How do you convert N mm to J?
- When does the trapezium rule underestimate the area?
- What energy transfer occurs when a stretched spring launches a trolley?
- If the stored energy doubles, by what factor does the speed of the object it launches change?
- Why is the work done in stretching not F × x?
Exam questions on Elastic strain energy
- A spring of stiffness 250 N m⁻¹ obeys Hooke's law. It is extended by 0.060 m.The spring is attached to a trolley of mass 0.30 kg on a frictionless horizontal track. When released from this extension, all of the stored energy becomes kinetic energy of the trolley. Calculate the maximum speed of the trolley.2 marks
- A metal wire obeys Hooke's law up to a force of 40 N, at which its extension is 2.0 mm.A student calculates the work done in stretching the wire to 40 N as 40 N × 2.0 mm = 0.080 J. Explain why this is incorrect and give the correct value.2 marks
- A strip of elastic polymer is stretched within its elastic limit, and the force is measured at 2.0 mm intervals of extension. The readings are: 0 N at 0 mm, 3.0 N at 2.0 mm, 5.0 N at 4.0 mm, 6.0 N at 6.0 mm and 6.5 N at 8.0 mm. The graph of force against extension is a curve whose gradient decreases as the extension increases.Estimate the elastic energy stored in the strip when its extension is 4.0 mm.3 marks
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).