If an object with a mass of #2 kg # changes speed from #2 m/s# to # 4m/s#, by how much does its kinetic energy change?

1 Answer
Jun 14, 2018

Answer:

#12 # Joules

Explanation:

Given: mass #= 2 kg#, changes speed from #2 m/s " to " 4 m/s#. Find the #Delta KE#

#KE = 1/2 mv^2#

#Delta KE = 1/2 mv_2^2 - 1/2 m v_1^2#

#Delta KE = 1/2 (2)4^2 - 1/2 (2) 2^2#

The units #1 (kg*m^2/s^2) = 1 # Joule

#Delta KE = 16 - 4 = 12 # Joules

Since the mass stays the same you could have simplified the equation by factoring:

#Delta KE = 1/2 m (v_2^2 - v_1^2)#

#Delta KE = 1/2 (2) (4^2 - 2^2)#

#Delta KE = 16 - 4 = 12 # Joules