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

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