• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Conservation of Momentum Question Involving Two-Dimensions

  • Thread starter omgbeandip
  • Start date
1. The problem statement, all variables and given/known data
A grenade is rolling due west at 0.954m/s along a floor when it explodes into three pieces of equal mass. The first piece moves at 3.6m/s, 20° [N of W]. The second travels at 5.8m/s, 62° [S of W]. Calculate the velocity of the third piece.

2. Relevant equations
a^2 + b^2= c^2
Tan^-1 to find angle

3. The attempt at a solution
My attempt is in the attached image. I was curious if my masses were correct. Since they are all equal, I inputted 1 as my before component, and 1/3 for the 3 after components. Is this correct? And, are my calculations correct as well?



Staff Emeritus
Science Advisor
Homework Helper
Insights Author
Gold Member
2018 Award
Regarding the masses: You could simply assume that the grenade has a total mass ##m##, which will make the parts have mass ##m/3##. You will notice that ##m## cancels out of the final answer and thus that it does not matter what you chose for ##m##. In particular, ##m = 1\,\rm kg## should give the correct answer just as well as any other mass.

Want to reply to this thread?

"Conservation of Momentum Question Involving Two-Dimensions" You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving