more physics help!! 2 momentum problems?
QUESTION: Imagine a 505 g hockey puck is shot from Mario Lemiuex toward a 75 kg goalie at 48 m/s. If the goalie catches the puck and makes the save, what is the velocity of the goalie and the puck together after the puck is caught? ( is this elastic or inelastic ) ANSWER: .32 m/s rounded. I know the answer because the teacher told us. (i just dont know how to solve it, please show procedure! thanx!) QUESTION: A 0.20 Kg model railroad car moves with a speed of 0.24 m/s is struck from behind by an 0.42 kg model locomotive moving along the same line with a speed of 0.52 m/s. If they stick together after the collision, what is their velocity? ( is this elastic or inelastic ) ANSWER: .43 <-- from the teacher ( i dont know how to solve this either, please show procedure!) thanx i really appreciate this!
Public Comments
- Momentum of puck plus golaie before and after being caught are equal => (0.505)*(48) + 0 = (0.505 + 75)*v => v = (48) *(0.505/75.505) = 0.32 m/s Again, by momentum balance, (0.20)(0.24) + (0.42)(0.52) = (0.20 + 0.42)v => v = (0.048 + 0.2184) / 0.62 = 0.43 m/s Collision is completely ineleastic.
