Answer:
Explanation:
mass, m = 1400 kg
height, h = 16 m
initial velocity, u = 21 m/s
final velocity, v = 13 m/s
Work done by engine, We = 80 kJ
Let the work done by the friction force is Wf.
Use the work energy theorem
net work done = change in kinetic energy
work done by engine + work done by friction force + work done by the gravitational force = Change in kinetic energy
80000 + Wf - m x g x h = 0.5 m ( v² - u²)
80000 + Wf - 1400 x 9.8 x 16 = 0.5 x 1400 x ( 169 - 441 )
- 139520 + Wf = - 190400
Wf = 50880 J
