Question

A car is approaching a traffic light at 18.0 m/s when the light turns red. The driver takes 0.80 s to react and puts his foot on the break pedal after the car decelerates at 2.0 m/s^2 . What is the stopping distance?

Answer 1

Apply 2nd equation of motion .

Answer 2

\(\sf v_f^2=v_i^2+2a\Delta x\)

\(\sf (0)^2=(18~m/s)^2+2(- 2.0 m/s^2)\Delta x\)

solve for \(\sf \Delta x\)