Question: What is the mass of the turtle hanging on the string?
Observation: We found it curious that there was no need to calculate any horizontal forces.
Question: What is the reading on the spring scale?
Observation: Since the forces are equal and there is no relative motion, we can measure as if it were a single force acting upon the scale.
Question: Find the expression of frictional force using U.
Observation: There is minimal friction between the ladder and the wall.
Question: What is the friction between the block and ramp.
Observation: Because of the minimal friction in the pulley, we can assume the two masses are directly related.