[问答题]
A ball is attached to a
stjxn9ic- fop; *l eth0i d,i*0dum.:i*x(dvfi,f2oma8 efi ) sji r(75z.a o horizontal cord of length L whose other end is fixed (Fig.
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(a) If the ball is released, what will be its speed at the lowest point of its path?
(b) A peg is located a distance h directly below the point of attachment of the cord. If h=0.8L what will be the speed of the ball when it reaches the top of its circular path about the peg?
