Originally Posted by

**Qcalc101** Hey,

I was having a little trouble with these two calculus word problems. I would appreciate any help that I can get. Thanks a lot.

1) Let R be the shaded region bounded by the graph of y = lnx and the line

y = (x - 2).

a) Find the area of R.

b) Find the volume of the solid generated when R is rotated about the horizontal line y = -3.

c) Write, but do not evaluate, an integral expression that can be used to find the volume of the solid generated when R is rotated about the y-axis.

2) At an intersection in Thomasville, Oregon, cars turn left at the rate

L(t) = 60$\displaystyle square root (t)$ $\displaystyle sin^2(t/3)$ cars per hour over the time interval 0 <= t <= 18.

a) To the nearest whole number, find the total number of cars turning left at the intersection over the time interval 0 <= t <= 18 hours.

b) Traffic engineers will consider turn restrictions when L(t) >= 150 per hour. Find all values of t for which L(t) >= 150 and compute the average value of L over this time interval. Indicate units of measure.

c) Traffic engineers will install a signal if there is any two-hour time interval during which the product of the total number of cars turning left and the total number of oncoming cars traveling straight through the intersection. Does this intersection require a traffic signal? Explain the reasoning that leads to your conclusion.