A gymnast of mass 40 kg40\text{ kg}40 kg jumps off a raised platform and lands on a soft safety mat. When she reaches the safety mat, she takes 160 milliseconds160\text{ milliseconds}160 milliseconds to slow down and come to a complete stop. During this landing, an average force of 1500 N1500\text{ N}1500 N is exerted on her feet by the safety mat. Calculate the velocity of the gymnast at the instant she first touched the mat. Show your working.
6 exam-style questions on AQA GCSE Physics 5.7 Momentum (HT only), covering 5.7.1 Momentum is a property of moving objects, 5.7.2 Conservation of momentum, and 5.7.3 Changes in momentum. Each one has a worked solution and a mark scheme showing where the marks go.