- #1
Helly123
- 581
- 20
Homework Statement
For number 3,4,5
https://s4.postimg.org/qbp3xzq65/IMG_1092.png
https://s22.postimg.org/u220j60sx/IMG_1093.png
Homework Equations
Centripetal force = m v^2/R
T = centripetal force + w
Sigma F = m.a
The Attempt at a Solution
Number 3. Find the v at D point using mechanic energy eternity
While kinetic energy at A point is zero, and the potential energy is max (height max)
So, 1/2mvD^2 + mg.hD = 1/2mvA^2 + mg.hA
i don't know the height at D point...
After i find the v at D
I can find T
Which T = centripetal Force + weight
T = mvD^2/R + m.g
Number 4 almost the same
The string doesn't bend (what exactly it means...?)
So, centripetal force > weight??
m.vD^2/R > m.g ...(1)
But why the centripetal at point D has opposite direction than weight force? Is it because the string stuck at the nail at C point??
Find the v at D using mechanical energy eternity then add v to ...(1)
Number 5 i still don't know...
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