relvel50

Apparent velocity of wind

The actual velocity of the wind and the apparent velocity of the wind are two different things. For example, if you are running at 5 m/s and there is a wind straight in your face of 2 m/s, then the wind appears to you to have a velocity of 7 m/s.

In these problems, let the velocity of the wind be

Write down the given velocity of the person, vp, & find the velocity of the wind relative to the person (how the wind appears to the person), using the formula  if the apparent velocity is from the east or west, the j-= 0 & from the north or south, the i = 0.

from the SW or NE, i = j from the SE or NW, I = -j

So usually in these question the wind appears to come from one direction when the person travels in one direction, and from another direction when the person goes another direction. As long as you use the formula above for both scenarios, (remembering that the velocity of the wind does not change (and express it in the i & j vectors)) then we simply manufacture the appropriate simultaneous equations and solve.

hitting a moving target ?? a 1000kg cannon fires a 2kg ballista from it, when it does so it gets an instant velocity of m/s, what speed does it fire the cannon ball at?

if the cannon ball has its furthest range when it is inclined at an angle 45o to the ground, how far will the cannonball travel,

if the cannon crew have a target that will pass them on a road, that at its nearest point will be at maximum range of the cannon, and the car passes at