- Car A Starts Braking 2 Just Before Impact Just Before Impact 3 Just After Impact 3 Just After Impact 4 Final Positio 1 (109.79 KiB) Viewed 84 times
- Car A Starts Braking 2 Just Before Impact Just Before Impact 3 Just After Impact 3 Just After Impact 4 Final Positio 2 (34.72 KiB) Viewed 84 times
Find the coefficient of friction between the tyre & the road from the FBD of the friction block W = 9 x9.81 N = 88.29 N Free body diagram of the friction block P = 75.8 N Friction block F. N.
Find the frictional force on the 2 cars between point 3 and point 4 with the aid of FBD of the cars WI V3 = ? V4 = 0 Free body diagram of the 2 cars together A B continue (Fr)3-4 (N.)3-4
Determine the friction force after Car A collide with Car B dragging it along 12.15m. Work-Energy Principle: Since the distance between point 3 & point 4 is known, Work-Energy Method is can be applied directly: E3 + U3-4 = E4
Determine V3 using the work-energy method from point 3 to 4. Conservation of Momentum Principle must be applied during impact Total momentum just before impact M2 = ma VA2+ MB VB2 Total momentum just after impact M3 = ma V3 + me V3 Using the Conservation of Momentum Principle M2 = M3 =
Using the above conservation of Momentum Princeiple to deter V2. Before the impact (from point 1 to point 2) Only car A is involved in the analysis before the impact Same coefficient of friction found previously, u = 0.8585, is applicable WA VA1 = ? VA2 = 20.27 m/s Free body diagram of car A A (Fr) 1-2 (Nr)1-2 (Fr)1-2 = u (Nr)1-2 :
using the above equation to determine the friction friction when car A is braking before impacting onto car B. Since the distance between point 1 & point 2 is known, Work-Energy Method is can be applied directly: E1 = K1 = 12 mA VA12 = U1-2 = EF X S1-2 E2 = K2 = 12 mA VA22 = Work-Energy Principle: E1 + U1-2 = E2
Apply work-energy priinciple to determine Va1. using Newton's Second Law for linear motion: EFx = ma aa - - (Fr)1-2 = ma aa =