1. The problem statement, all variables and given/known data Two carts collide. Cart A has a mass of 300 Kg and a velocity of 24 m/s. Cart B has a mass of 100 Kg and is stationary. Both carts have 20 m springs on them. Assume that the two carts exert no force on each other until the springs touch at a seperation of d= 40 m, and then exerts a repulsive force of 600 N on the other. 2. Relevant equations I'm supposed to find the velocities, momentums and displacements of the carts after the collision but the problem is, there is no spring constant. My understanding of Hooke's law leads me to believe that as springs compress, their repulsive force increases, so why are the springs repulsive forces constant, it just doesn't make any sense to me what so ever. 3. The attempt at a solution I attempted to solve it by assuming that the cart will slow down at a rate of 4 m/s^2 because F= ma and since F is 1200 and m is 300, a must be 4. Problem is, I can't calculate the amount of compression of the spring because there is no spring constant and I don't know the velocities of the other cart... It's just so confusing.