Inches and centimeters are different units of measurement, one English, one metric. Converting from one to the other requires use of a conversion factor.
One such factor can be derived from 1 inch = 2.54 cm. This means that one inch is 2.54 times longer than one cm.
We want to find 
such that 
. This means
Integrating both sides of the latter equation with respect to 
tells us
and differentiating with respect to 
gives
Integrating both sides with respect to gives
Then
and differentiating both sides with respect to 
gives
So the scalar potential function is
By the fundamental theorem of calculus, the work done by 
along any path depends only on the endpoints of that path. In particular, the work done over the line segment (call it 
) in part (a) is
and does the same amount of work over both of the other paths.
In part (b), I don't know what is meant by "df/dt for F"...
In part (c), you're asked to find the work over the 2 parts (call them 
and 
) of the given path. Using the fundamental theorem makes this trivial:
Nothing times itself will equal 29, but in decimal form only is 5.38
The quotient of 675 and 5 would be 135.
675/5=135
Hope this helps!
