Highway safety engineers build soft barriers so that cars hitting them will slow down at a safe rate. a person wearing a safety belt can withstand an acceleration of 300 m/s 2. how thick should barriers be to safely stop a car that hits the barriers at 92.8 km/h? answer in units of m.

Question

Physics

Angus

11 December, 11:03

Highway safety engineers build soft barriers so that cars hitting them will slow down at a safe rate. a person wearing a safety belt can withstand an acceleration of 300 m/s 2. how thick should barriers be to safely stop a car that hits the barriers at 92.8 km/h? answer in units of m.

+4

Answers (1)

Know the Answer?

Isis Middleton · Answer 1

Basically, we want to see the distance in terms of thickness. So, for this rectilinear motion at constant acceleration, the equation to be used is:

x = v₀t + 0.5at²

First, let's determine t using the equation:

a = |v - v₀|/t

300 m/s² = |0 - 92.8 km/h * 1,000 m/1 km * 1 h/3600 s|/t

t = 0.086 seconds

x = (92.8 km/h * 1,000 m/1 km * 1 h/3600 s) (0.086 s) + 0.5 (300 m/s²) (0.086 s) ²

x = 3.33 meters