4. KE increases by a factor of 16 is the answer
Explanation:
Kinetic energy = (1/2)mv² = 0.5 mv²
where
m = mass, and v = velocity.
So at 15 mph,
K E = 0.5 m (15) ² = 112.5 m
And at 60 mph,
K E = 0.5 m (60)² = 1800 m
m is the mass, and not meters.
So, 1800 m/112. 5 m = 16
16 times the Kinetic Energy.