Simple Mechanics confusing me:S

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Homework Help Overview

The problem involves a boy whirling a stone in a horizontal circle and analyzing the motion after the string breaks. The subject area is mechanics, specifically focusing on circular motion and projectile motion.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss using kinematics to find the initial speed of the stone and subsequently calculate the centripetal acceleration. Some express confusion regarding their calculations and assumptions.

Discussion Status

There is an ongoing exploration of different methods to solve the problem. Some participants have provided guidance on finding the time of fall to determine horizontal speed, while others reflect on their previous assumptions and calculations.

Contextual Notes

One participant noted a misunderstanding regarding the initial conditions, specifically assuming the initial vertical speed was zero, which they later recognized as incorrect.

brandon26
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A boy whirls a stone in a horizontal circle of radius 1.2 m and at height 1.7 m above ground level. The string breaks, and the stone flies horizontally and strikes the ground after traveling a horizontal distance of 10 m. What is the magnitude of the centripetal acceleration of the stone while in circular motion?

Please help!
 
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Use the kinematics of projectile motion to find the initial speed of the stone. Then use that speed to calculate the centripetal acceleration.
 
Doc Al said:
Use the kinematics of projectile motion to find the initial speed of the stone. Then use that speed to calculate the centripetal acceleration.

yes, I used V^2=u^2 + 2as , where V=0 and u is the speed to be found. But the answer comes out wrong.
 
Try finding the time it takes for the object to fall. Then use that time to calculate the horizontal speed.
 
Wicked. Got the answer right by working out the time. Thanx.
PS. i got the firwst answer wrong because I assumed that V= o , but that was false
 

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