1. The problem statement, all variables and given/known data A projectile with a mass of 20 g has an initial horizontal velocity of 100 m/s when it hits and stops in a wood block of mass 0.402 kg. The block is sitting on a horizontal frictionless surface and is attached to a massless spring, initially relaxed, with spring constant 143 N/m. What is the maximum compression of the spring? 2. Relevant equations P= MV K=1/2 MV^2 F=-kx 3. The attempt at a solution Initial Momentum of the Bullet = .02 x 100 = 2 Initial momentum of the Bullet/Wood system = 2 due to conservation of momentum. 2= .404 V V= 4.95 m/s is the velocity of the block/bullet system. K = 1/2 (.404) 4.95^2 K= 4.95 Due to conservation of Energy, this is also the amount of energy the spring exerts. 4.95 =143X Wrong. I suspect the error in my calculation is near the end, but I don't know that for certain.