Question

A blue car with mass mc = 528 kg is moving east with a speed of vc = 17 m/s and collides with a purple truck with mass mt = 1352 kg that is moving south with an unknown speed. The two collide and lock together after the collision moving at an angle of θ = 59° South of East


a. What is the magnitude of the initial momentum of the car?

b. What is the magnitude of the initial momentum of the truck?

c. What is the speed of the truck before the collision?

d. What is the magnitude of the momentum of the car-truck combination immediately after the collision?

e. What is the speed of the car-truck combination immediately after the collision?

Answer 1

a. momentum of car (Pc) = mass*velocity
momentum = (528kg)*(17m/s)
= 8976 kg*m/s

Note: we need to find part c first

b. momentum of truck (Pt) = mass*velocity
momentum = (1352kg)*(11m/s)
= 14872 kg*m/s

c. tan(θ) = (momentum truck/momentum car)
tan(59°) = (1352*v)/(8976)
solve for v
v = 11 m/s

d. total momentum = sqrt(Pc^2 +Pt^2)
total momentum = sqrt((8976^2)+(14872^2))
= 17370.81 kg*m/s

e. final velocity = (total momentum)/(total mass)
= 17370.81/(528+1352)
= 9.24 m/s

Note: The magnitude of the TOTAL momentum of the system before and after the collision will be the same.