Frames of reference problem help(grade 12)

In summary: So the resultant velocity is (7.08+6.0) or 13.08 m/s. In summary, the boat's velocity is 13.08 m/s in a current of 2.41 m/s.
  • #1
bigmac
16
0

Homework Statement


A boat goes at 7.78 m/s [37 degrees west of south] in a current of 2.41 m/s [5 degrees north of west]. Find the velocity compared to the bottom.


Homework Equations


I think we use this: Vf2 = Vi2 + 2a x delta d


The Attempt at a Solution



I drew a diagram but don't know how to post it here...
 
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  • #2
You must add the two vectors. They are in different directions, so it is a bit complicated. One method is to find the horizontal (East/west) and the vertical (north/south) components of each vector. Then add the horiz and vertical vectors separately. Sketch these two vectors head-to-tail to add them. You'll see that you need to find the hypotenuse to get the total and use some trig to find the direction.

An alternate method is to sketch the original vectors head-to-tail, then draw a line from beginning to end - the "resultant" or total of the other two vectors. This makes a triangle and you can solve for the resultant side using both the law of sines and the law of cosines.

Welcome to the Physics Forum!
 
  • #3
AWESOME! I know how to do that. I did a lot of those where you add the x and y components to get the resultant displacement or velocity. And yes my diagram is a head-to-tail diagram. Ill do it that way. So the velocity I get will be the velocity compared to the bottom? I'll post my final answer can you check please?

And thanks for the fast reply :biggrin: I'll be visiting here quite often :biggrin:
 
  • #4
this is how I did it...is this right?

17tjbs.jpg
 
  • #5
Take another look at your first diagram. It would be a good idea to show the x and y components on there. Both of the x components are in the same direction (left) so you get 2.4 + 4.68 = 7.08 to the left. You may wish to call this -7.08.
In the y direction, the 6.21 is down and the 0.21 up, so you get a total of 6.0 down.
 

FAQ: Frames of reference problem help(grade 12)

What is a frames of reference problem?

A frames of reference problem is a type of physics problem that involves analyzing the motion of an object from different perspectives or frames of reference. This can help us understand how an object's motion appears to change depending on the observer's point of view.

How do you solve a frames of reference problem?

To solve a frames of reference problem, you can follow these steps:

  • Identify the frames of reference involved in the problem.
  • Define the direction and magnitude of the object's motion in each frame of reference.
  • Use equations and principles of kinematics to analyze the motion in each frame of reference.
  • Compare the results from each frame of reference to understand how the object's motion appears to change.

What are the different types of frames of reference?

There are two main types of frames of reference: inertial and non-inertial. An inertial frame of reference is one in which Newton's laws of motion hold true and there are no accelerating forces acting on the object. A non-inertial frame of reference is one in which an object appears to be accelerating due to a non-zero net force acting on it.

Can frames of reference affect the measurement of an object's motion?

Yes, frames of reference can affect the measurement of an object's motion. This is because an object's motion appears different depending on the observer's point of view. For example, an object may appear to be at rest in one frame of reference but moving in another. This is why it is important to consider different frames of reference when analyzing motion.

How are frames of reference used in real-world applications?

Frames of reference are used in various fields, such as physics, engineering, and navigation. In physics, frames of reference are used to understand the motion of objects in different scenarios. In engineering, they are used to design structures and machines that can withstand different frames of reference, such as those on a moving vehicle. In navigation, frames of reference are used to determine the position and velocity of objects in relation to a fixed point or frame of reference, such as in GPS systems.

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