Question

please answer these both questions

Answer 1

26]
initial velocity = u = 30m/s
final velocity = v = 20m/s
time = t = t
retardation = a = ?

a = v-u/t
a = 20-30/5
a = -10/5
a = -2m/s²

distance = s = ?
s = ut + at²/2
s = 30(5) + (-2)(5)²/2
s = 150 - 50/2
s = 150-25
s = 125 m

27]
initial velocity = u = 72km/h = 72×5/18 = 20m/s
final velocity = v =36km/h = 36×5/18 = 10m/s
distance = s = 200m
retardation = a = ?

v² - u² = 2as
10² - 20² =2(a)(200)
100-400 = 400a
-300 = 400a
a = -300/400
a = -0.75 m/s²
a = -0.75×10^2 cm/s²
a = -0.75×100 cm/s²
a = -75cm/s²