Question

A car traveling at 60 mph has how much more energy than a car going at 15 mph? KE increases by a factor of _____. 4 1/4 16 1/16

Answer 1

KE increases by the square of the speed.  Since the first car is moving 4 times faster, its KE is 16 times higher

Answer 2

Answer with explanation:

Kinetic Energy of a body is given by the formula

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

Kinetic Energy of Car having speed 60 mph

               $\rightarrow K.E_{1}=\frac{m \times (60)^2}{2}\\\\=1800 m$    

Kinetic Energy of Car having speed 15 mph

               $\rightarrow K.E_{2}=\frac{m \times (15)^2}{2}\\\\=\frac{225 m}{2}$      

$\Rightarrow\frac{K.E_{1}}{K.E_{2}}=\frac{1800}{\frac{225}{2}}\\\\=8 \times 2\\\\=16$

Kinetic energy of Car Traveling at 60 mph has 16 times more energy than a car going at 15 mph.