Please explain the last 3 parts of the bottom question. It looks like we would h
ID: 1639026 • Letter: P
Question
Please explain the last 3 parts of the bottom question. It looks like we would have to assume momentum to be conserved in part I to get that speed is constant? But why?
Please explain why!!
The answers for part I: speed stays the same
art 2: momentum decreases
part 3: KE decreases
Suppose an open railroad car is rolling without friction/air resistance and then four large blocks of ice are dropped vertically into the car. What happens to the following quantities as the blocks are dropped and carried off in the railroad car? Note: Consider the railroad car" to be the car itself and anything in it. ICE CE I. What happens to the speed of the "railroad car"? II. What happens to the momentum of the "railroad car"? Ill. What happens to the KE of the "railroad car"? Some time later, the four large blocks of ice that had been dropped vertically into the railroad car melted. As the car/water rolled along the frictionless track without air resistance, the water started todrain out of a hole in the bottom of the railroad car. What happens to the following quantities as the water drains out? Note: Consider the "railroad car" to be the car itself and anything in it. WATER I. What happens to the speed of the "railroad car"? II. What happens to the momentum of the "railroad car"? Ill. What happens to the KE of the "railroad car"?Explanation / Answer
when ice blocks falls in the railroad car
I) as the ice blocks falls in the railroad car , the total mass of the car increases. hence to keep the momentum constant or same , the speed of railroad car decreases.
II) Momentum of the car remains same as the net force on the system is 0
III) Kinetic energy of railroad car decreases since this is an example of inelastic collision and in inelastic collision there is loss of kinetic energy
As the water drains out of the car , the mass of the car becomes equal to when it was before ice blocks fell in it. hence the car regains its original speed
momentum of the car remains same