If an object with a mass of #2 kg # changes speed from #6 m/s# to #2 m/s#, by how much does its kinetic energy change?

1 Answer
May 13, 2018

Answer:

So the kinetic energy was reduced by a factor of #4#. Or, equivalently, the kinetic energy was reduced by #27 "J"#.

Explanation:

Before:

#E_k = 1/2mv_i^2 = 1/2(2)(6)^2 = 36 " J"#

After:

#E_k = 1/2mv_f^2 = 1/2(2)(3)^2 = 9 " J"#

So the kinetic energy was reduced by a factor of #4#. Or, equivalently, the kinetic energy was reduced by #27 "J"#.