Question

Mobil balap formula 1 direm dengan perlambatan konstan dari kelajuan 144km/jam menjadi 72km/jam dalam jarak 50 m. berapa jarak total yang ditempuh mobil balap tersebut sampai benar - benar terhenti?

Answer 1

Is know
v₂  = 144 km/jam
v₁  = 72 km/jam
v₃ = 0 km/jam
s₂  = 50 m
Asked
st
Answer
v₂ = 144 x 1000 / 3600 = 40 m/s
v₁ = 72 x 1000 / 3600 = 20 m/s
v₃ = 0 km/jam = 0 m/s

a = v₂² - v₁² / 2s₀
a = 40²-20² / 2 . 40
a = 1600 - 400 / 80
a = 1200/80
a = 15 m/s₂

s₃ = - 1/2 (v₂² - v₁² / a)
s₃ = - 1/2 (0²-15² / 15)
s₃ = - 1/2 (0-225 / 15
s₃ = - 1/2 (-225/15)
s₃ = - 1/2 (-15)
s₃ = 7,5 m

st = s₁ + s₂ + s₃
st = 0 + 50 + 7,5
st = 57,5 m