Two automobiles of equal mass approach an intersection. One vehicle is traveling
ID: 1610363 • Letter: T
Question
Two automobiles of equal mass approach an intersection. One vehicle is traveling with velocity 12.0 m/s toward the east and the other is traveling north with speed v_2i. Neither driver sees the other. The vehicles collide in the intersection and stick together, leaving parallel skid marks at an angle of 61.0 degree north of east. Determine the initial speed v_2i of the northward-moving vehicle. The speed limit for both roads is 35 mi/h and the driver of the northward-moving vehicle claims he was within the speed limit when the collision occurred. Is he telling the truth? Yes NoExplanation / Answer
a) Let the final speed be v
from conservation of momentum towards north
2mv sin61 = mv2i
applying conservation of momentum in east
2mv cos61 = m x 12
from the above equations
tan 61 = v2i/12
v2i = tan 61 x 12 = 1.8040 x 12
= 21.65 m/s
b) speed limit = 35mph = 35 x 0.44704 m/s = 15.65 m/s
i.e a > b
hence he is lying