The displacement of a particle from a fixed point O O\,O at time t t\,t seconds is s=(t3−15t2+62t) ms=(t^3-15t^2+62t)\text{ m}s=(t3−15t2+62t) m.
Find the initial velocity of the particle.
Find the time at which the acceleration is zero.
260 exam-style questions on OCR A Level Maths 3.2 Kinematics, covering 3.2.1 Language of kinematics, 3.2.2 Graphs in kinematics, 3.2.3 Displacement-time and velocity-time graphs, 3.2.4 Constant acceleration formulae, 3.2.5 Constant acceleration in two dimensions (A-level only), 3.2.6 Non-uniform acceleration in one dimension (A-level only), 3.2.7 Non-uniform acceleration in two dimensions (A-level only), 3.2.8 Motion under gravity using vectors (A-level only), and 3.2.9 Projectiles (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.