CoE questions

PFY p.121

19

a) W = m x g

= 50 x 10

= 500g

b) GPE = m x g x h

    = 50 x 10 x 4

    = 2,000J

c) Energy In = Energy Out

KE = 2,000J

Collins, p.91

Q3

a) GPE = m x g x h

    = 35 x 10 x 30

    = 10,500J 

b) KE = 1/2 x m x (v^2)

    10,500 = 1/2 x 35 x (v^2)

    v = 24.5 (24.49489743)

c) The actual speed at the bottom of the hill is likely to be less than the value calculated in part b because there is friction from the snow and her sledge. The friction reduces the speed as she goes down the hill.