Find Velocity: Help Solve Ball Problem

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Homework Help Overview

The problem involves two balls being thrown vertically downward from the same height, with the first ball thrown at an initial velocity of 5 m/s. The question seeks to determine the velocity at which the second ball should be thrown after 2 seconds to collide with the first ball in the subsequent 2 seconds.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss the timing of the throws and the conditions under which the balls will meet. Some express confusion regarding the direction of the second ball's throw, while others clarify that both balls are thrown downward. There is also mention of calculating distances traveled and final velocities as part of the reasoning process.

Discussion Status

The discussion includes various interpretations of the problem setup, with some participants questioning assumptions about the direction of the throws. There is an acknowledgment of the need to equalize the distances traveled by both balls to find a solution, and some participants have begun to outline their thought processes.

Contextual Notes

Participants note that the height from which the balls are thrown is not specified, but it must be sufficient for the first ball to be in flight for the required time. There are also reminders about forum rules regarding the need for participants to show their work before receiving assistance.

Prasun-rick
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So the question which is troubling me is as follows:
A ball is thrown vertically down with velocity of 5 m/s.With what velocity should another ball be thrown down after 2 seconds so that it can hit the 1st ball in next 2 seconds.

I couldn't ses the way out..as I feel the height of the 1st ball should be given...but I know I can be wrong..so please help me ..and thanks in advance.
 
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The balls are thrown from the same spot. It doesn't matter how high that spot is above the ground as long as the spot is high enough that the first ball can be in flight for the required time before the second ball hits it. How long will the first ball have been in flight before the second ball hits it?
 
TSny said:
The balls are thrown from the same spot. It doesn't matter how high that spot is above the ground as long as the spot is high enough that the first ball can be in flight for the required time before the second ball hits it. How long will the first ball have been in flight before the second ball hits it?
welll...as far as I understood...the first ball was thrown vertically downwards and the second vertically upwards...and coming to your question the first ball would have stayed 4 sec in flight before the second one hits it...I guess :)
 
Prasun-rick said:
welll...as far as I understood...the first ball was thrown vertically downwards and the second vertically upwards...and coming to your question the first ball would have stayed 4 sec in flight before the second one hits it...I guess :)
But how to solve after that??..please help!
 
Prasun-rick said:
welll...as far as I understood...the first ball was thrown vertically downwards and the second vertically upwards...
The problem states that both balls are thrown downward.
and coming to your question the first ball would have stayed 4 sec in flight before the second one hits it...I guess :)
Yes. Good. What can you calculate that would be helpful in answering the question?
 
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Prasun-rick said:
welll...as far as I understood...the first ball was thrown vertically downwards and the second vertically upwards...and coming to your question the first ball would have stayed 4 sec in flight before the second one hits it...I guess :)

Why do you claim that the second ball is thrown upwards. The question says, very clearly "... another ball be thrown down... "--so thrown down, not up.
 
TSny said:
The problem states that both balls are thrown downward.
Yes. Good. What can you calculate that would be helpful in answering the question?
Well yes...sorry It was my fault...indeed the second was thrown downwards too...
And I think I can calculate the distance they have traveled and also their final velocities !
 
Prasun-rick said:
And I think I can calculate the distance they have traveled and also their final velocities !
OK
 
Ray Vickson said:
Why do you claim that the second ball is thrown upwards. The question says, very clearly "... another ball be thrown down... "--so thrown down, not up.
yess...very sorry...It was my fault..I kept having a delusion that it was thrown upwards
 
  • #10
TSny said:
OK
okay...then what to do?..Please help me out !..Should I equalise their distance travelled??..Will that be helpful?
 
  • #11
You said you could calculate the distance traveled. Please show your work.

Note: Homework helpers are required to obey the Forum rules. One of the rules is not to help until the poster has filled out the template and shown some attempt at solving the problem. So, I'm already verging on getting fired here :oldsmile:
 
  • #12
TSny said:
You said you could calculate the distance traveled. Please show your work.

Note: Homework helpers are required to obey the Forum rules. One of the rules is not to help until the poster has filled out the template and shown some attempt at solving the problem. So, I'm already verging on getting fired here :oldsmile:
okay thank you...I figured it out ..I just equalized the two distance !
 
  • #13
Prasun-rick said:
okay thank you...I figured it out ..I just equalized the two distance !
Good work!
 

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