A 15,000 kg railroad freight car travels on a level track at a speed of 2.5 m/s. It collides and couples with a 25,000 kg second car, initially at rest and with brakes released. What is the speed of the two cars coupled together after collision?

Can somebody explain to me how newton's 3rd law relates to momentum? ~ap physics 1

Orque can be calculated by multiplying the force (n) applied at 90? to the lever arm at a distance (m) from the pivot point (point of rotation), the compound si unit for the torque is n? m. if the force (at 90? to the lever arm) applied is 15 n and it is applied at 2.0 m from the pivot point (point of rotation), what is the torque on the lever?

Could someone me find the answer to this problem.