How Do You Calculate Change in Momentum Without Mass?

AI Thread Summary
To calculate the change in momentum without knowing the mass of the ball, focus on the concept of momentum per unit mass, which is equivalent to the velocity. The problem specifically asks for momentum per unit mass, so you can directly use the recorded velocity values from your experiment. The sign of the velocity is important and depends on your chosen direction for positive values; if the ball is falling downwards, it would typically be negative. Thus, the change in momentum per unit mass can be determined by analyzing the velocity data collected during the impacts. Understanding these principles will allow you to solve the problem effectively.
amanda.ka
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Homework Statement


I did an experiment where I dropped a ball beneath a motion sensor and it recorded the vertical components of position vs time, velocity vs time, and acceleration vs time.
The question asks to determine the change in the ball's linear momentum (per until mass) during the 5 selected impacts with the ground. I know that the equation for linear momentum is p = (mass)(velocity) however the experiment did not say to weigh the ball so I do not have "m". How would I go about solving this? Also I know that momentum is a vector quantity so the sign is important. Does that mean my velocity values would be negative as the ball is falling towards the ground? Thanks in advance!

Homework Equations


p = mv

The Attempt at a Solution

 
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amanda.ka said:

Homework Statement


I did an experiment where I dropped a ball beneath a motion sensor and it recorded the vertical components of position vs time, velocity vs time, and acceleration vs time.
The question asks to determine the change in the ball's linear momentum (per until mass) during the 5 selected impacts with the ground. I know that the equation for linear momentum is p = (mass)(velocity) however the experiment did not say to weigh the ball so I do not have "m". How would I go about solving this?
Note that the problem didn't ask you for the momentum but the momentum per unit mass.

Also I know that momentum is a vector quantity so the sign is important. Does that mean my velocity values would be negative as the ball is falling towards the ground? Thanks in advance!
This depends on your sign convention. Which direction do you want to call the positive direction? If the ball's velocity is in that direction, it would be positive; if it's in the opposite direction, it would be negative.

Homework Equations


p = mv

The Attempt at a Solution

 
vela said:
Note that the problem didn't ask you for the momentum but the momentum per unit mass.

Does this mean that the linear momentum would just be equal to the velocity?
 
Yes, the momentum per unit mass is just the velocity.
 
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