a juggler

Asked by ashwinivg | 10th Oct, 2010, 04:10: PM

Expert Answer:

When the juggler will throw the 7th ball the first ball would have came back into his hand. Thus the ball reached its maximum height in half of the time ie, 7/2 seconds, therefore
 
H = 1/2*a*t2=1/2*10*49/4 = 5*49/4
 
Therefore maximum energy will be the kinetic energy of the ball when it reaches back the juggler, which is equal to the Potential energy at the top,
 
Max. Energy = K.E. = P.E. = mgH
thus, 1/2*m*v2 = mgH
Thus we will get the maximum velocity from,
 
ie, v =  =  = 5*7 = 35m/s.
Hence option b is correct.
 
Thanks,
Team Topper

Answered by  | 10th Oct, 2010, 05:21: PM

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