An elastic cord of spring constant k k\,k is stretched from its natural length to an extension of 2x2x2x. The cord is then allowed to partially contract to a smaller extension of x x\,x over a time interval ttt.
What is the average power delivered by the elastic cord during this contraction?
3kx22t\frac{3 k x^2}{2 t}2t3kx2
kx22t\frac{k x^2}{2 t}2tkx2
3kx2t\frac{3 k x^2}{t}t3kx2
2kx2t\frac{2 k x^2}{t}t2kx2
84 exam-style questions on AQA A Level Physics Force, energy and momentum, covering Scalars and vectors, Moments, Motion along a straight line, Projectile motion, Newton's laws of motion, Momentum, Work, energy and power, and Conservation of energy. Each one has a worked solution and a mark scheme showing where the marks go.