I\'m working on Ballistic Pendulum Scenario, and I have a couple questions I cou
ID: 2263771 • Letter: I
Question
I'm working on Ballistic Pendulum Scenario, and I have a couple questions I could really use some help with. In this scenario:
You will fire a paintball into a pendulum bob and measure how far it moves horizontally. Knowing that the pendulum swings in a circular arc allows you to calculate to what height it rose. From the maximum height to which it rose, you can then deduce the velocity it had at the bottom of the swing (using conservation of mechanical energy). The velocity at the bottom of the swing is the velocity after the collision of the paintball with the pendulum bob.
a.) Since the velocity and therefore the momentum of the pendulum and ball are zero at the heigh "h," how can we say that momentum is conserved in this experiment?
b.) Comment on the following statement: "The momentum of the paintball and bob could not be conserved in this experiment beacuse of the large frictional forces between the bob and the entering paintball."
Thanks!!
You will fire a paintball into a pendulum bob and measure how far it moves horizontally. Knowing that the pendulum swings in a circular arc allows you to calculate to what height it rose. From the maximum height to which it rose, you can then deduce the velocity it had at the bottom of the swing (using conservation of mechanical energy). The velocity at the bottom of the swing is the velocity after the collision of the paintball with the pendulum bob. Since the velocity and therefore the momentum of the pendulum and ball are zero at the heigh "h," how can we say that momentum is conserved in this experiment? Comment on the following statement: "The momentum of the paintball and bob could not be conserved in this experiment beacuse of the large frictional forces between the bob and the entering paintball."Explanation / Answer
A) During collision with the bob tension in the string and weight of the system,which is the centripetal force are the only forces acting on it and it is normal to the motion of the bob
B)During the collision momentum is conserved because tension and weight,the only forces acting on the system is perpemdicular to the direction of motion and hence no effect on momentum
C)During circular motion momentum is not conserved because forces such as weight and tension start acting in the direction of motion