If an object with a mass of #5 kg # changes speed from #12m/s# to # 8m/s#, by how much does its kinetic energy change?

1 Answer
Apr 6, 2016

Answer:

#Delta E_k=-200 J#

Explanation:

#"data :"#
#m=5" kg 'mass of object'"#
#v_i=12" m/s ' initial velocity of object'"#
#v_l=8" m/s 'final velocity of object'"#
#E_k=1/2*m*v^2" The kinetic energy of object"#

#E_i=1/2*5*12^2#

#E_i=(5*144)/2#

#E_i=360 " J the initial kinetic energy of object"#

#E_f=1/2*5*8^2#

#E_f=5*64/2#

#E_f=160 " J the final kinetic energy of object"#

#Delta E_k=E_f-E_i#

#Delta E_k=160-360#

#Delta E_k=-200 J#