physics
posted by rock .
In one day, a 85 kg mountain climber ascends from the 1440 m level on a vertical cliff to the top at 2360 m . The next day, she descends from the top to the base of the cliff, which is at an elevation of 1310 m .
a) What is her gravitational potential energy on the first day? If you choose the reference level for zero potential energy at:
a. the top of the cliff.
b. 1440 m level.
c. 1310 m level.
b) What is her change in gravitational potential energy on the first day?
c) What is her change in gravitational potential energy on the second day?

m g (H  Ho) where mg = 85*9.81 = 834 N
first day
If Ho = 2360
U at start = 834 (14402360)
U at top = 834 (23602360) = 0
If Ho = 1440
U at start = 834 (14401440) = 0
U at top = 834 (2360  1440)
If Ho = 1310
U at start = 834 (1440  1310)
U at top = 834 (2360  1310)
b) U at top  U at start
834(2360  1440)
c) U at end  U at top
834 (1310  2360)