Answer:
The speed of the wind is 25 km/hr.
Explanation:
Let us call the speed of the plane and
the speed of the wind. When the plane is flying against the wind, it covers the distance of 900-km in 2 hours (120 minutes); therefore;
(1).
And when the plane is flying with the wind, it covers the same distance in 1 hour 48 minutes (108 minutes)
(2).
From equation (1) we solve for and get:
,
and by putting this into equation (2) we get:
or in km/hr this is
Answer:
Explanation:
For an object to move with constant velocity, the acceleration of the object must be zero:
.
As the net force equals acceleration multiplied by mass , this must mean:
.
So, the sum of the three forces must be zero:
,
this implies:
.
To obtain this sum, its easier to work in Cartesian representation.
First we need to define an Frame of reference. Lets put the x axis unit vector pointing east, with the y axis unit vector
pointing south, so the positive angle is south of east. For this, we got for the first force:
,
as is pointing north, and for the second force:
,
as is pointing west.
Now, our third force will be:
But, we need the magnitude and the direction.
To find the magnitude, we can use the Pythagorean theorem.
this is the magnitude.
To find the direction, we can use:
and this is the angle south of east.