Question

Part A

Assume: in the y (vertical) direction: up is positive; in the x (north-south) direction: north is positive.

Henry drives his car north at velocity 21.1 m/s, passing Annabelle, the stationary observer, standing on a street corner. If Annabelle sees rain falling straight down at constant velocity -45.3 m/s, find the speed of the rain, in m/s, according to Henry.

Part B

In the 19^th century, barges were pulled by rope through the Erie Canal. Suppose two ropes of equal length make an angle θ = 48.8^o to each other. Assume the frictional force between the boat and the water, opposing its forward motion, is 6.24x10⁵ N, and that, on average, each man pulls with a constant force of 667 N. Find the total number of men needed to pull the boat at constant velocity through the canal.

NOTE: Since you cannot have a fraction of a man, you must raise the answer to the nearest whole man (so 123.1 becomes 124).

Answer 1