Tag: Physics

21 Nov by Zarir.Hafiz Tags: , ,

How to Determine Speed from Skid Marks

A skid mark is a tyre mark on the road surface produced by a sliding tyre due to locked wheels. A skid mark typically appears very light at the beginning of the skid getting darker as the skid progresses and comes to an abrupt end if the vehicle stops at the end of the skid.… Read More
5 Nov by Iskandar Abdul Hamid Tags: , ,

Speed calculation based on projectile motion

Data: Bus height, hbus = 3.743m CG height =hCG = 3.743/3 = 1.248m CG tilt, htilt = 2.60/2 = 1.30m. Guardrail height, hG = 1.05m Change in CG height, h = hG + htilt – hCG = 1.102m d = 10.52m   The angle that will give the minimum speed is calculated using equation “θ”=1/2 … Read More
20 Oct by Zarir.Hafiz Tags: , ,

Coefficient of friction vs Drag factor

Drag factor and coefficient are expression commonly used in crash investigation and reconstruction. They are usually used to calculate vehicle speed calculations based upon tyre mark geometry. The coefficient-of-friction μ is defined as the ratio of the tangential force F(tan) (parallel to the surface) applied to an object sliding across a surface to the normal… Read More