Question

Problem-2 The steepest section of rond in Seattle is the 200ft-long section of E. Roy street from 25th Ave E. at the top to 26th Ave E at the bottom. That section of E. Roy has a 21% grade (the angle of inclination angle of the road is 11.9º.) One day, Alyssa is traveling at the posted speed limit of 25mi/hr downhill on E. Roy between 25th Ave E. and 26th Ave E. She suddenly notices the stop sign hidden behind a tree branch when she is a distance d = 25ft from the intersection at 26th Ave E. Alyssa's car has ABS brakes, and her tires have a coefficients of friction ( x) = (0.7,0.5) on this section of road. What distance is required for Alyssa to stop her car? Is she able to stop her car before the stop-sign?

Answer 1

Here we apply concept of kinematics and Newton's laws of motion. We apply equation of motion for constant acceleration.

৬, = 1|)+ 6 M/s free bady dinaa NA As car Mofien Lo kiretic fciction wil. AТ Normal ferce Ne = 0.5 Lgiven) Pexpendicular to He traak ae motian + Cap MpSinG-fy het Aley the incline Co m/SSir 1-9- o5) Ceas9 accelexationof can 2.44M a initial ve lecifyisoyinal velocity=n y +2a d Aappiny tence PI46M9 +2-2-77 - 22.5 me tex = 73.8 dd . ao she Canot top Distance reqires to tp =73-84d 1