Answer:
The workdone is 
Explanation:
The free body diagram is shown on the first uploaded image
From the question we are given that
The force is on the force gauge 
The distance that Magnus pulled the bus
Generally the workdone by the tension force on Magnus is


This negative sign show that is tension force is in the opposite direction to Magnus movement (i.e the movement of the bus )
Substituting value we have


Answer:
Explanation:
Length if the bar is 1m=100cm
The tip of the bar serves as fulcrum
A force of 20N (upward) is applied at the tip of the other end. Then, the force is 100cm from the fulcrum
The crate lid is 2cm from the fulcrum, let the force (downward) acting on the crate be F.
Using moment
Sum of the moments of all forces about any point in the plane must be zero.
Let take moment about the fulcrum
100×20-F×2=0
2000-2F=0
2F=2000
Then, F=1000N
The force acting in the crate lid is 1000N
Option D is correct
A cold acetic acid solution is used to wash the residue of
the reagent in preparation of an aldol condensation product after vacuum
filtration. The main reason in washing
with the acetic acid rinse is to neutralize any sodium hydroxide.