sure this isn't backwards?A man can row at 24 km/h, and run at 7 km/h.
and this ... sure it's not distance from A to B down (parallel) to the beach?The direct distance from A to B is 25 km
This is in preparing us for optimization in calculus, yet i dont understand how this diagram will look or how to solve it, can someone give someone pointers?
A man can row at 24 km/h, and run at 7 km/h. He needs to get from a point A, on the south bank of a stretch of still water, to point B on the north bank of the water. The direct distance from A to B is 25 km, and the water is 24 km wide. He starts rowing with an angle theta between North and the direction in which he rows. Find an expression for the time T he will take to get from A to B, in terms of theta.
What is the speed of running use for?
thanks in advance
These type of "time" optimization starter problems are usually designed so that part rowing and part running will achieve the least amount of time. There are some (like this) that yields the least time for all rowing (or all running) depending on the problem set-up ... but these usually don't come until after you've solved a couple of starter problems.
No matter ...
= time in hrs
= distance shown in the sketch
obviously, the minimum time will be a bit over an hour if the person rows directly from A to B. you can check the minimum w/ a graph on your calculator
This is what happens when a problem's parameters aren't checked against the real world ... no thought at all in setting it up, imho.
it would take an Olympic athlete to row a boat at a rate of 24 km/hr for over an hour.
my grandmother can walk faster than 7 km/hr.