Question

Western Carolina University Dept. of Chemistry & Physics PHYS 230-01: General Physies I Instructor: Dr. Mesfin Woldeyohannes Quiz # 2 (September 08, 2017) Time Allowed: 15 Minutes NAME: 1) Uniformly Accelerated Motion I (10 Points) A car travelling at 25 mi/h is to stop on a 35-m long shoulder of the road (a) What is the required magnitude of the minimum deceleration? b)How much time will elapse during this minimum deceleration until the car stops?
I want to answer question 1 a and b

Answer 1

Initial velocity, $u= 25 mi/h= 25 \times \frac{1609.34m}{60 \times 60 s}= 11.176 m/s$

Length of road covered, D= 35m

Final velocity, v= 0m/s (Since finally the car stops)

a). Let deceleration be "a", then using Equations of motion,

  (ANS) (Negative sign shows deceleration)

b). Let time taken be "t", then using equations of motion

  (ANS)