If an object with a mass of #2 kg # changes speed from #19m/s# to #20 m/s#, by how much does its kinetic energy change?

1 Answer
Jan 16, 2016

Answer:

#39J#, increase

Explanation:

Kinetic Energy of an object is given by
#E_k=1/2 m v^2#, where #m# is the mass and #v# the velocity* of the body.
In the given question, if #v_i# and #v_f# are the final and initial velocities respectively
Change in kinetic energy #Delta E_k =1/2 m (v_f^2-v_i^2)#
Substituting given values
#Delta E_k =1/2 .2. (20^2-19^2)#

*Even though velocity is a vector quantity, Kinetic energy is a scaler quantity because #v^2# i a scaler quantity.