Thread: Bearing / trigonometry

Hi everyone,
i am trying to Solve this question but I'm a bit clueless i probably have to use trigonometry.

À Ship is heading out to Sea at à bearing of 28 degrees at a Constant speed. At 10:04 hours it is 5.2km due West of the Port and at 10:40hours it is due North of the Port. Radio contact with the Port can Be maintained up to distance of 32 km.

Assuming that the Ship continues its course unchanged, determine its bearing from the Port at 11:10hours and the Time at which Radio contact with the Port will Be Lost.

Thank you in Advance

Originally Posted by MickG86

Hi everyone,
i am trying to Solve this question but I'm a bit clueless i probably have to use trigonometry.

À Ship is heading out to Sea at à bearing of 28 degrees at a Constant speed. At 10:04 hours it is 5.2km due West of the Port and at 10:40hours it is due North of the Port. Radio contact with the Port can Be maintained up to distance of 32 km.

Assuming that the Ship continues its course unchanged, determine its bearing from the Port at 11:10hours and the Time at which Radio contact with the Port will Be Lost.

Thank you in Advance

1. Draw a sketch defining a coordinate system.

2. The position of the ship at 10:04 is (-5.2, 0). The position of the ship at 10:40 is (0, 9.7798). Calculate the distance traveled during these 36 minutes to get the speed of the ship in .

3. Calculate the distance traveled during the time from 10:04 to 11:10. With this distance and the known angle you can determine the position of the ship.

4. Use the Cosine law to determine the position where radio contact isn't possible.

Originally Posted by earboth

1. Draw a sketch defining a coordinate system.

2. The position of the ship at 10:04 is (-5.2, 0). The position of the ship at 10:40 is (0, 9.7798). Calculate the distance traveled during these 36 minutes to get the speed of the ship in .

3. Calculate the distance traveled during the time from 10:04 to 11:10. With this distance and the known angle you can determine the position of the ship.

4. Use the Cosine law to determine the position where radio contact isn't possible.

hi sorry to bring up an old thread but i got this exact same question.

i was wondering if someone could explain in a bit more detail, i don't really understand earboth's response. (for example where did the 9.7798 come from? and how you use the distance between 10:04 to 11:10 to find the bearing? )

many thanks.