argument over a simple physics problem...?
i'm from saudi arabia, and my physics teacher and i had a little argument about a physics problem (of course), so i want you to answer this simple question of addition and subtraction (rough translation):
"a boat is moving in a river with a speed of 2.5 m/s relative to the water. while a monitor standing on the bank of the river measures its speed and finds it to be 0.5 m/s relative to him. what is the river water's speed? and is it moving in the same direction as the boat or the opposite direction?"
our argument wasn't about the speed, it was about the direction. i say it's opposite and he says it's the same direction. he says that there's a "mistranslation" in the question from the american book (even though "the teacher's book" says it's opposite).
Comments
I hate to get in the middle of a teacher student debate. On the other hand, it's not the end of the world kind of debate.
The only way he could observe (on the shore I presume) a speed slower than what the boat is moving is if the two components (river speed and boat speed) were in opposite directions. The net motion of the river is - 2 m/s which would bring the boat's speed down to 0.5 m/s. The boat must be going in the opposite direction at 2.5 m/s
If the river was standing still and not moving, the boat's speed would be 2.5 m/s.
I go with you.
your teacher is wrong.
its opposite..
because you need to push the water back to go forward. its obvious that the water facing to the shore pulls you away from it.
you should call another physics teacher about this and let him answer you.