A car with a mass of 1,400 kg and a speed o 15 m/s heading north approaches an i
ID: 2033711 • Letter: A
Question
A car with a mass of 1,400 kg and a speed o 15 m/s heading north approaches an intersection. At the same time, a minivan with a mass of 1,800 kg and speed of 20 m/s heading east is also approaching the intersection. The car and the minivan collide and stick together. What is the velocity of the wrecked vehicles just after the collision? Ignore friction between the tires and the surface of the road. (Enter the magnitude in m/s and the direction in degrees counterclockwise from due east.) magnitude direction m/s o counterclockwise from due eastExplanation / Answer
Using momentum conservation
In x-direction
Pix = Pfx
m1V1xi + m2*V2xi = (m1 + m2)*Vxf
V1xi = 0
Vxf = Vf*cos A = m2*V2xi/(m1 + m2)
m1 +m2 = 3200 kg
Vf*cos A = 1800*20/3200 = 11.25 m/sec
Similarly
In y-direction
Vyf = Vf*sin A = m1*V1yi/(m1 + m2)
Vf*sin A = 1400*15/3200 = 6.56 m/sec
Vxf = 11.25 m/sec
Vyf = 6.56 m/sec
Vf = sqrt (Vxf^2 + Vyf^2)
Vf = sqrt (11.25^2 + 6.56^2)
Vf = 13.02 m/sec
Angle theta will be
A = arctan (Vyf/Vxf)
A = arctan (6.56/11.25) = 30.25 deg
Vf = 13.02 m/sec at 30.25 deg CCW from east
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