Question

Let you are running at 15 meter/sec and declerates at 4 meter/sec square

a. how long will you have take to stop
b. how far will you go while declerating

Answer 1

a. 3.75 s b. 28.125 m

Step-by-step explanation:

Data

Vi = 15 m/s

Vf = 0 m/s

a = -4 m/s²

i) t = ?

ii) S = ?

Solution

i) Using Newton's 1st Eq of Motion

Vf = Vi + at

t = (Vf - Vi) / a

t = (0 - 15) / -4

t = 3.75 s

ii) Using Newton's 3rd Eq of Motion

2aS = Vf² - Vi²

S = (Vf² - Vi²) / 2a

S = (0² - 15²) / 2 x -4

S = 28.125 m