- Messages
- 313
- Reaction score
- 50
- Points
- 38
but how do we know that the velocity of lifeboat relative to ship is 45 km/h ?? and is it necessary to use the scales?First find the relative velocity im pretty sure u guys know that
use the equation
V(L/S) = V(L) + (-V(S))
then use a scale of possibly 1 cm = 5km/h and plot a relative velocity line at a bearing of 270* which should if i remember it correctly about 9 cm then make an arrow showing that its moving towards the left !
Now connect the -V(s) line towards the left end of the relative velocity line u made before in such a way that u make 150* so the angle between the relative line and this new line is 60* now this line should be of 3 cm !
Last just join the remaining line to the figure and u got the diagram now use cosine rule for first part then sine rule and a bit of bearing knowledge in second part that all