A railway car of mass m1 travelling at a velocity of v1 collides with a second car of mass m2 travelling at v2 and the two join together. What is their final velocity?
Momentum is conserved in any collision, and for a single body is given by p = mv. The momentum before is m1v1+m2v2, and the momentum after is (m1 + m2)u where u is the final velocity, so the final velocity is (m1v + m2*v2)/(m1 + m2).
Related Physics A Level answers
All answers ▸what depends if the universe is expanding or not
A ball is launched from ground level at 5m/s at an angle of 30 degrees above the horizontal. What is its height above ground level at the highest point in its trajectory?
Two current carrying wires are placed next to each other and anti-parallel currents are allowed to flow. Is the magnetic force between the wires attractive or repulsive?
A conical pendulum is a mass suspended from a point that traces out a horizontal circle. By balancing the weight with the tension in the string, determine the speed of the bob.