Question

which has greater cenetic energy a car traveling 30.0 km/hr or one twice as heavy traveling at 15 km/hr?​

Answer 1

30 km/h car

Explanation:

From analysis the car traveling at 30 km/h has greater kinetic energy

we can deduce it from the expression of kinetic energy which is

`KE=(1)/(2) mv^2`

Assuming the mass m= 1 kg

For the 30 km/h

`KE=(1)/(2)*1*30^2 \\\\KE=(1)/(2)*1*900\\\\\KE=450 J`

For the 15 km/h

`KE=(1)/(2)*2*15^2 \\\\ KE=(1)/(2)*2*225 \\\\\ KE=(1)/(2)*450 J\\\\\ KE=225 J`

Though the kinetic energy is a function of mass and velocity, but from our analysis the faster moving object has more KE