Answer:
783.2 N.m or Joules
Explanation:

Work done when a force F is applied to move an object by a displacement d meters
where cos(Ф) is the angle between applied force F and displacement d
Since the weightlifter is applying the force upward and the set of weight also move upward therefore, both are in same direction hence angle will be zero.
Now lets substitute the given values into the work equation:

since cos(0)=1


or

Since the unit of Force is Newton (N) and the unit of displacement is meters (m) therefore, unit of work done will be N.m
Note: 1 N.m is equivalent to 1 joule
1) Do > 2f
Do means object distance
2f means 2 x focal length
2 x focal length = radius of curvature
When an object is placed beyond the radius of curvature, a real image is formed between the radius of curvature and focus. The image size is reduced. The sketch is shown below
The change in the total energy of the object is zero (0).
The given parameters:
work done by the machine, W = 50 J
mass of the object, m = 10 kg
To find:
the change in the total energy of the object
The change in the total energy of the object is the difference between the objects initial energy due to its position and the work done on the object.
Based on work energy-theory, the work done on the object is equal to the energy of the object.
- The energy of the object = work-done on the object
- The change in total energy = 50 J - 50 J = 0
Thus, the change in the total energy of the object is zero (0).
Learn more here: brainly.com/question/20377140