# physics

posted by .

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. Using a Vector diagram, what is the resultant?

Hi, I am completely new to this, and missed a lot of classes due to hospital trips. Trying to catch up but there is no sample question in my text like this one. I don't really know how to get the numbers to make the vectors. Can you lead me in the right direction, would be very much appreciated, thank you very much.

The answer they get is 60.5 degrees north or 29.5 degrees north of east, but they show no work, just the answer. When I draw out the vectors, what do I use to determine the length of each vector? The hours? The knots? What scale 1mm = 1hour, or 1mm = 1knot?

Steve was nice enough to give me a hand, but me not being the smartest one on the block is still a little confused. Thank you Steve, very much appreciated!!! This site is the best.

• physics -

Math books drive me crazy with their misuse of navigational language. You travel on a heading as used in the second sentence. A bearing is what direction you look to see something. (The enemy is on a bearing of 185 degrees true.)
Anyway start at (x,y) = (0,0)
It is heading 25 deg east of north
in x-y coordinates that is 25 degrees clockwise from the Y axis so we would say
X velocity = 4 sin 25 = 1.69 knots
Y velocity = 4 cos 25 = 3.625 knots
after three hours x = 3*1.69 = 5.07 nautical miles
and y = 3*3.625 = 10.875 nautical miles

Now we turn south (negative y axis)
go south for two hours at 5 knots = 10 nautical miles
so in the end after 5 hours
x position = 5.07 naut miles
y position = 10.875-10 = .875 naut miles
so that position on you x-y graph is
(5.07, .875 )
tan angle up from x axis = y/x =.875/5.07
so angle up from x = 9.79 degrees
so angle clockwise from north = 90-9.79 = 80.2 degrees east of north.
If you want it in km rather than nautical miles, multiply all distances by 1.852

• physics -

Sorry the answer they have is 60.5 degrees east of of north or 29.5 degrees north of east. There would be two vectors right, so do you take the degrees from the resultant? Thanks Damon, I do not nothing about this stuff at all. The question says my answer should be found by drawing, so it may not match.

• physics -

I gave the wrong answer at first. Sorry.

• physics -

Thanks Damon, figured it all out thanks to your people's help, you rock. Thanks buddy!!!

## Similar Questions

1. ### physics

Two vehicles with the same mass collide and lock together traveling 28 m/s at 37 degrees north of east after the collision. How fast was the car traveling that was heading north while the other vehicle was traveling east?
2. ### math

. A boat is travelling on a bearing of 25° east of north at a speed of 5 knots (a knot is 1.852 km/h). After travelling for 3 hours, the boat heading is changed to 180° and it travels for a further 2 hours at 5 knots. What is the …
3. ### math

Two fishing boats depart a harbor at the same time, one traveling east, the other south. The eastbound boat travels at a speed 1 mi/h faster than the southbound boat. After nine hours the boats are x = 45 mi apart. Find the speed of …
4. ### physics

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. …
5. ### physics

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. …
6. ### physics

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. …
7. ### physics

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. …
8. ### physics

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. …
9. ### Pre-calculas

Boat A leaves a dock headed due east at 1:00 PM traveling at a speed of 16 mi/hr. At 2:00 PM, Boat B leaves the same dock traveling due north at a speed of 18 mi/hr. Find an equation that represents the distance d in miles between …
10. ### Pre-calc

Boat A leaves a dock headed due east at 1:00PM traveling at a speed of 13 mi/hr. At 2:00PM, Boat B leaves the same dock traveling due north at a speed of 20 mi/hr. Find an equation that represents the distance d in miles between the …

More Similar Questions

Post a New Question