The stopping distance s of a car varies directly as the square of its speed v. If a car traveling at 40 mph requires 112 ft to stop, find the stopping distance

Question

The stopping distance s of a car varies directly as the square of its speed v. If a car traveling at 40 mph requires 112 ft to stop, find the stopping distance for a car traveling at 55 mph

Answer 1

Hi Hannah,

 

the equation to solve this problem  would look like the following

 

s = v²/k

 

The stopping distance s will increase (varies directly) as the velocity increases.

 

putting in the values we know

 

112= 40²/k

 

k = 112/1600

 

k = 14.286

 

at 55 mph we would have

 

s = 55²/14.286

 

s = 211.75 ft to stop

 

hope this helps