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Energy and circular motion?

A 5.5 kg ball is spun on a thin cord in a

vertical circle having 3.81 m radius. It has

a speed of 16.7 m/s at the highest point of

the circle. Take zero potential energy at the

lowest point and use the 69

angle measured

with respect to the vertical as shown.

The acceleration of gravity is 9.8 m/s

What minimum speed v0 is required to keep

the ball moving in a circle?

Answer in units of m/s

This is my last problem and i don't know where to start help would be nice thank you.

1 Answer

Relevance
  • Anonymous
    1 decade ago
    Favorite Answer

    For zero tension in the string at the top of the swing, the centripetal acceleration would equal that of gravity.

    v^2/R = g

    v = (gR)^1/2

    v = (9.80x3.81)^1/2

    v = 6.11m/s

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