Answer:
Student’s(50 kg) gravitational potential energy if the cliff is 80 m high = 39.2 kJ
Explanation:
Potential energy is given by the expression, PE =mgh, m is the mass, g is the acceleration due to gravity value and h is the height.
Here mass of student, m = 50 kilogram
Height of cliff , h = 80 meter
Acceleration due to gravity =
Potential energy, PE = 50 * 9.8 * 80 = 39200 J
= 39.2 kJ
Student’s(50 kg) gravitational potential energy if the cliff is 80 m high = 39.2 kJ
Answer:
Work done, W = 1.44 kJ
Explanation:
Given that,
Mass of boy, m = 74 kg
Initial speed of boy, u = 1.6 m/s
The boy then drops through a height of 1.56 m
Final speed of boy, v = 8.5 m/s
To find,
Non-conservative work was done on the boy.
Solution,
The work done by the non conservative forces is equal to the sum of total change in kinetic energy and total change in potential energy.
W = 1447.21 Joules
or
W = 1.44 kJ
Therefore, the non conservative work done on the boy is 1.44 kJ.