CoE questions 19 August 2011 17:00 PFY p.121 [cid:image001.png@01CC72E7.51FD2C20] Collins, p.91 [cid:image002.png@01CC72E7.51FD2C20] Answers PFY p121 a) W = m x g --> W = 50 x 10 = 500N CORRECT
b) GPE = W x h --> 500 x 4 = 2000J CORRECT
c) Total E at Start = Total E at End --> 2000J = KE + 0 --> 2000J CORRECT Answers PFY p91 a) GPE = mgh --> 35 x 10 x 30 = 10500J CORRECT
b) GPE at top = KE at bottom --> KE = 1/2 mv^2 --> v = sqr(10500/(35/2)) = 24.5 m/s CORRECT
c) There is friction from the snow and the sledge, which converts the KE into heat energy; therefore not all of the GPE is transferred to KE as that energy is 'wasted' CORRECT
b) GPE = W x h --> 500 x 4 = 2000J CORRECT
c) Total E at Start = Total E at End --> 2000J = KE + 0 --> 2000J CORRECT Answers PFY p91 a) GPE = mgh --> 35 x 10 x 30 = 10500J CORRECT
b) GPE at top = KE at bottom --> KE = 1/2 mv^2 --> v = sqr(10500/(35/2)) = 24.5 m/s CORRECT
c) There is friction from the snow and the sledge, which converts the KE into heat energy; therefore not all of the GPE is transferred to KE as that energy is 'wasted' CORRECT
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