Question

Q1. My brakes stop me at -5.5m/s^2 when I lock them up. A puppy runs in front of my car, and I stop just in time 3.5 seconds later. How far did I skid? Q2. I floor the pedal and accelerate from 7.0m/s to 35m/s over a fouth of a mile (0.40km). What is my accelleration?

please explain step by step, much thanks :)

Answer 1

Step-by-step explanation:

Q1. Given:

v = 0 m/s

a = -5.5 m/s²

t = 3.5 s

Find: Δx

Δx = vt − ½ at²

Δx = (0 m/s) (3.5 s) − ½ (-5.5 m/s²) (3.5 s)²

Δx ≈ 33.7 m

Q2. Given:

Δx = 400 m

v₀ = 7.0 m/s

v = 35 m/s

Find: a

v² = v₀² + 2aΔx

(35 m/s)² = (7.0 m/s)² + 2a (400 m)

a = 1.47 m/s²