The following values have been provided:
weight w = 240 lb = 1,067.52 N
energy E = 3,000 J
The equation for potential energy is:
E = w h
where h indicates the height that the person needs to ascend, therefore:
h = 3000 / 1067.52
h = 2.81 m
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<span>Thus, he must ascend 2.81 meters</span>
We will use the equations of rotational kinematics,
(A)
(B)
Here, 
and 
denote the final and initial angular displacements, respectively, whereas 
and 
represent final and initial angular velocities, and 
is the angular acceleration.
We are provided with 
and 
.
By substituting these values into equation (A), we have
Now, using equation (B),
This indicates that the wheel's angular speed at the 4.20-second mark is 36.7 rad/s.
Objects will stay in a stationary position if the total force acting on them amounts to zero; this occurs when equal forces are applied in opposite directions. According to Newton's second law, if the net force on an object is zero, it will not move.
Response:
D: The distance among the particles diminishes
Clarification:
Removing energy reduces the activity of molecules, similar to how one slows down in cold temperatures (I believe).
