Average speed = (total distance covered) / (time to cover the distance)
Total distance covered = (9.5m + 3.5m + 15m) = 28 meters
Time to cover the distance = 43 seconds
Average speed = (28 meters) / (43 seconds)
Average speed = 0.65 meters/second
Rotational motion may be described analytically for bodies undergoing pure rotation.
Let the rescue boat starts at an angle theta with the North
now its velocity towards East is given as


now in some time "t" it will catch the boy
so we will have

also we have

now we have



by solving above we got

When multiple forces are at work on an object, the net force is called a <em>resultant</em>, because it's a sum of vectors, and a sum of vectors is called their resultant.