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

Answer:

30 km/h car

Step-by-step 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

$KE=\frac{1}{2} mv^2$

Assuming the mass m= 1 kg

 

For the 30 km/h

$KE=\frac{1}{2}*1*30^2 \\\\KE=\frac{1}{2}*1*900\\\\\KE=450 J$

   

For the 15 km/h

$KE=\frac{1}{2}*2*15^2 \\\\ KE=\frac{1}{2}*2*225 \\\\\ KE=\frac{1}{2}*450 J\\\\\ KE=225 J$

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