100 likes | 368 Views
Reaction Time and Breaking Distance. Stopping distance: consists of the reaction distance plus the braking distance. 1. Reaction distance: Distance the vehicle moves during the time it takes to react ( reaction time ) and apply the brake. Δ d. v =. Δ d r = v t r. t.
E N D
Reaction Time and Breaking Distance
Stopping distance: consists of the reaction distanceplus the braking distance. 1. Reaction distance: Distance the vehicle moves during the time it takes to react (reaction time) and apply the brake. Δd v = Δdr= v tr t t x v = Δd
2. Braking distance Depends on two factors: • how fast the car is going (and how big it is) • condition of the road. Slippery roads provide less friction with the tires – longer breaking distance. Friction constant (k) A number given to show how slippery it is on a surface. Thehigher the number, the more slippery. ∆db = k v2
Δdr = vtr ∆db = kv2 Stop distance = Δdr + ∆db
Suppose you are riding in a car travelling at 70 km/h or 19.4 m/s on in the rain. You spot a deer in the road. Your reaction time is 1.15 s. What is your stopping distance? v = 19.4 m/s tr = 1.15 s k = 0.10 19.4 19.4 1.15 0.10 Δdr = vtr ∆db = kv2 = = = = 22.3 m 37.6 m Stop distance = Δdr + ∆db = 59.9 m
Δdr = vtr ∆db = kv2 Stop distance = Δdr + ∆db
Δdr = vtr ∆db = kv2 Stop distance = Δdr + ∆db 70 km/h ? 50 m