Alberta Free Tutoring And Homework Help For Physics 30

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1.A 950 kg car is moving west when it collides with a 1800 kg truck moving north. After the collision, the car is moving at 22.0 km/h at 31oW of N and the truck is moving at 17.0 km/h at 25oN of W. Determine the speed of both vehicles before the collision.

3 years ago

Answered By Emily D

This is impulse! We're going to assume that no energy is lost in the collision (purely elastic, not plastic).

Here is the equation you want: you can break it down into North/South (y) and East/West (x) components

m1v1' + m2v2' = m1v+ m2v2

Given Information:

m1 = 950

m2 = 1800

v1y' = 0 (car was moving West, no North/South velocity)

v1 = 22.0km/h at 31o W of N

v2x' = 0 (truck was moving North, so no E/W velocity)

v2 = 17.0 km/h at 25o N of W

x-components, East is +, West is -

950(vx) + 1800(0) = -950(22*sin(31)) - 1800(17*cos(25))

vx = - 40.523 km/h

 

y-components, North is +, South is -

950(0) + 1800(vy) = 950(22*cos(31)) + 1800(17*sin(25))

vy = 17.137 km/h

 

So, initially, the car was traveling at 40.5 km/h West and the truck was traveling at 17.1 km/h North