mechanical engineering
posted by Anonymous .
A railroad car that weighs 20,000 lb is traveling eastward with a
velocity whose magnitude is 5fps. A second car, on the same track, that
weighs 40,000 lbs also traveling in an easterly direction with a
velocity of 7.8fps. When the cars collided, they became coupled together
and then both cars moved with the same velocity. If friction between the
cars and the rails is neglected, what were the magnitude and the
direction of the velocity of the car after the collision?

Momentum before = m1 v1 + m 2 v2
Momentum after = (m1+m2) v
then
momentum after = momentum before.
Respond to this Question
Similar Questions

Physics
Car A is traveling at 84 km/h while Car B is traveling at 58 km/h. What is the relative velocity of Car A to Car B if they both are traveling in the same direction? 
Physics
Car A is traveling at 84 km/h while Car B is traveling at 58 km/h. What is the relative velocity of Car A to Car B if they both are traveling in the same direction? 
college physics
A(n) 13,300 lb railroad car traveling at 7.4 ft/s couples with a stationary car of 6790 lb. The acceleration of gravity is 32 ft/s^2. What is their velocity after the collision (ft/s)? 
PHYSICS
A car traveling at a constant velocity of 30.0 m/sec passes an intersection at time t=0. 45 seconds later a second car passes the same intersection and its traveling in the same direction at a constant velocity of 55 m/sec. when does … 
PHYSICS
a car traveling at a constant velocity of 30 m/sec passes an intersection at time t=0 45 seconds later a second car passes the same intersection and its traveling in the same direction at a constant velocity of 55 m/sec. when does … 
physics
A 1,225kg car traveling initially with a speed of 25.0 m/s in an easterly direction crashes into the rear end of a 8,500kg truck moving in the same direction at 20.0 m/s. The velocity of the car right after the collision is 18.0 … 
Physics
A police car traveling at 94.5 km/h is traveling west, chasing a motorist traveling at 77.2 km/h. (a) What is the velocity of the motorist relative to the police car? 
physics
A car initially traveling eastward turns north by traveling in a circular path at uniform speed as in the figure. The length of the arc ABC is 259 m, and the car completes the turn in 38.0 s. a)Determine the car's speed.m/s b)What … 
Physics
A two head collision. One car weighs 45000 newtons and going at 15 meters per second. The other car is traveling at 25 meters per second and weighs 9000 newtons. How would I calculate velocity? 
Terzulum
a car A is 200m behind car B both are traveling in the same direction, initial velocity 25m/s starting their motion at the same time they accelerate at 30, car A overtook car B after 20sec this time car B was travelin at the velocity …