Physics
posted by sam c on .
Car A has a mass of 1000kg and a speed of 60km/h, and car b has a mass of 2000kg and a speed of 30km/h. what is the ratio of kinetic energy of car A to that of car b?

KE1 = m1•v1²/2,
KE2 = m2•v2²/2,
KE1/ KE2 = m1•v1²/ m2•v2²,
where
m1=1000 kg, v1 = 60000/3600 m/s,
m2=2000 kg, v2 = 30000/3600 m/s 
KE1= M1.v1'2/2
KE2= M2V2'2/2
KE1= [(1000kg)(277.89m'2/s'2)/2]
= 138944.45J
KE2= [(2000kg) (69.3889'2/s'2)/2]
= 69388.9J
KE1/KE2= 138944.45J/69388.9J
=2.00