If an object with a mass of #2 kg # changes speed from #9m/s# to #4 m/s#, by how much does its kinetic energy change?
1 Answer
Feb 18, 2016
Explanation:
The formula for kinetic energy is given by
#"KE" = 1/2 m v^2#
Initially, the kinetic energy is
#"KE"_"i" = 1/2 (2 "kg")(9 "m/s")^2#
#= 81 "J"#
In the end, the kinetic energy is
#"KE"_"f" = 1/2 (2 "kg")(4 "m/s")^2#
#= 16 "J"#
The change in kinetic energy is given by
#Delta "KE" = "KE"_"f" - # #"KE"_i#
#= 16 "J" - 81 "J"#
#= -65 "J"#