a car is traveling at 40.0 m/s. the drivers sees an emergeny ahead and 0.50 s later slams on the brakes. the acceleration of the car is -4.0 m/s^2.

Question

a. what distance will the car travel before it stops?
b. if the driver was able to apply the brakes instantaneously without a reaction time, over what distence would the car stop?
c. assume your car was traveling at 30.0 m/s instead. without performing any calculations, would the answer now be less than, equal to or larger than before? explain your answer.

Answer 1

vi=40m/s
timedelay=.5s
a= -4m/s^2

vf^2=vi^2+2(-4)d
solve for d when vf=0, then

d= vi*t -1/2*4*(t-.5)^2

Answer 2

46