Elastic strain energyEdexcel International A Level Physics: Flashcards
What these 12 flashcards ask
- What is elastic strain energy?
- Give two equations for elastic strain energy of a spring obeying Hooke's law.
- Why is there a factor of ½ in Eel = ½Fx?
- How is strain energy shown on a force-extension graph?
- For a linear force-extension graph, what shape is the area under the graph?
- Can ½Fx be used if the force-extension graph is curved?
- Name two ways to estimate the area under a curved force-extension graph.
- How do you find the extra energy when a spring is stretched from x₁ to x₂?
- A spring (k = 250 N m⁻¹) is stretched by 0.080 m. What energy is stored?
- A spring fires a ball. Which energy equation can be used if no energy is lost?
- Where does lost energy go if a spring launcher is less than 100% efficient?
- What is the unit of elastic strain energy?
Exam questions on Elastic strain energy
- A spring of stiffness 250 N m⁻¹ is stretched by 0.080 m from its natural length. The spring obeys Hooke's law throughout.The spring is now stretched by a further 0.040 m. Calculate the additional elastic strain energy stored.2 marks
- A student stretches a strip of polymer, keeping it within its elastic limit. She records the force at each extension: 0 N at 0 m, 3.0 N at 0.050 m, 5.0 N at 0.100 m, 6.0 N at 0.150 m and 6.5 N at 0.200 m. The force is not directly proportional to the extension.Estimate the elastic strain energy stored in the strip when its extension is 0.100 m.2 marks
- A toy launcher contains a spring of stiffness 600 N m⁻¹. The spring is compressed by 0.050 m and then released, firing a ball of mass 0.025 kg along a horizontal barrel. The spring obeys Hooke's law throughout.Calculate the elastic strain energy stored in the compressed spring and hence the maximum speed of the ball, assuming all of the energy is transferred to the ball as kinetic energy.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).