If an object with a mass of #2 kg # changes speed from #2m/s# to # 7m/s#, by how much does its kinetic energy change? Physics Work and Energy Energy 1 Answer ali ergin Feb 17, 2016 #Delta E_k=45J# Explanation: #E_(k f) " :final kinetic energy"# #E_(k i):" initial kinetic energy"# #Delta E_k=E_(k f)-E_(k i)# #Delta E_k=1/2*m*(v_f^2-v_i^2)# #Delta E_k=1/2*2(7^2-2^2)# #Delta E_k=49-4# #Delta E_k=45J# Answer link Related questions How do matter and energy interact? Question #50ca2 Question #242cf Question #5038d Question #50391 What is potential energy? Question #d6576 Question #50cae Question #50cb2 Question #50cb6 See all questions in Energy Impact of this question 1294 views around the world You can reuse this answer Creative Commons License