Physics Help

  • Thread starter Nimmy
  • Start date
12. A hiker hears an echo 1.5 s after shouting over a valley. Estimate the width of the valley.

6. Two billard balls of equal mass undergo a perfeclty elastic head-on collison. If the speed of the white ball was initaially 2.00 m/s, and of the 8-ball 3.00 m/s in the oposite direction, what will be the final speed of the 8-ball?

7. A ball of the mass 2.0 kg moving east with a speed of 4.0 m/s collides head-on with a 0.92 kg ball at rest. If the collision is perfectly elastic, what will be the speed and direction of each ball after the collision?


Staff Emeritus
Science Advisor
Education Advisor
Insights Author
2018 Award
Please note that:

1. We have a HW help section

2. You have to show what you have done, or at least know SOMETHING about the question. We do not solve the problem for you.

Please read the Sticky in this section.


Want to reply to this thread?

"Physics Help" 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

Top Threads