# My homework question

1. Mar 5, 2009

### williamluffy

1. an airplanes flies a straight course form A to B and back again. the distance between A and B is L and the airplane mantains a constant airspeed V. there is a steady wind with a speed v.
a. find an expression. for the total trip time for an arbitrary wind direction. Notice that the trip time is always increased by the presence of a wind in any direction.

2. a pendulum of mass m and length L is released from rest in a horizontal position. a nail a distance d below the pivot causes the mass to move along the path indicated by the dotted line. find the minimum distance d in terms of L such that the mass will swing completely round in the circle.

2. Mar 5, 2009

### 09jk

for Q1. shouldnt the trips equation just be (2L)x(V)?
if its an up and back trip, the wind force shouldn't be worried about, because you will gain the same time for you trip back that you lost for your trip there, or vice versa

3. Mar 5, 2009

### thepopasmurf

That is actually incorrect, you don't gain the time back.

About the question though, when you say there is a constant airspeed, is that the speed of the plane relative to the wind or to the observer (its actual velocity)?