SIR\MADAM PLEASE EXPLAIN

Asked by  | 4th Nov, 2009, 08:20: PM

Expert Answer:

Dear Student

Initially total energy of Gayle  =  KE+PE = 1/2 X  mv2   +   mgh  =  1 /2  X 50 X 42 +  50X10X 15  =7900 J

Initial energy of sledge =  KE+PE= o+ 5X10 X 15  =750 J

Initially total energy of Gayle's brother = KE+PE = 1/2  X 30X 0 +  50X10X (15-5)  = 5000J

Total initial energy= 7900+750+5000= 13650 J

Final energy of both of them together with sledge =KE+PE =  1 /2  X (50+30+5) X V+0 = 42.5  V2

Total energy conserves  ==>  13650 =42.5  V==>  v2=  321.17  ==> V=  17.9 m/s

speed at the bottom of the hill if the total vertical drop is 15.0 m  =V=17.9 m/s

Regards

Team

Topperlearning

 

Answered by  | 12th Jan, 2010, 06:34: PM

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