Relative Motion Question (PHYSICS 20)

[whitsstar]

Homework Statement

You swim from the west to the eastern shore across a 30m wide section of the bow river at 3.5m/s @ 30° N of E. If the river flows southward at 4.0m/s, determine your resultant velocity/

Homework Equations

- Trig (SOH CAH TOA)

The Attempt at a Solution

So first I drew the vector 3.5 m/s @ 30° N of E and found y ( 1.75 m/s [N] ) and the x
( 3.031 m/s [E] ). From the question, 4.0 m/s - 1.72 m/s [N] = 2.25 m/s . Therefore, the new triangle would have x= 3.031 m/s and y= 2.25 m/s with hyp = 3.77m/s with the angle of 36.6

ANS = 3.8 m/s @ 37° S of E (??)

 

[Hootenanny]

Homework Statement

You swim from the west to the eastern shore across a 30m wide section of the bow river at 3.5m/s @ 30° N of E. If the river flows southward at 4.0m/s, determine your resultant velocity/

Homework Equations

- Trig (SOH CAH TOA)

The Attempt at a Solution

So first I drew the vector 3.5 m/s @ 30° N of E and found y ( 1.75 m/s [N] ) and the x
( 3.031 m/s [E] ). From the question, 4.0 m/s - 1.72 m/s [N] = 2.25 m/s . Therefore, the new triangle would have x= 3.031 m/s and y= 2.25 m/s with hyp = 3.77m/s with the angle of 36.6

ANS = 3.8 m/s @ 37° S of E (??)

Welcome to PF.

Your solution is correct

 

[baba89]

I would like to clarify a few things about this problem. First, it is important to note that the given velocities are likely in a two-dimensional plane, as the problem does not specify otherwise. Therefore, we can assume that the river and the swimmer's motion are both in the x-y plane.

Next, we should clarify the direction of the river's flow. The problem states that it flows southward, but this is not a specific direction. It could be southward in the x-direction, or in the y-direction, or at any angle in between. Without this information, it is difficult to accurately determine the resultant velocity.

Additionally, the given velocity for the swimmer is at a specific angle, but the direction of the river's flow is not specified. This means that the resultant velocity cannot be determined with just the given information.

In order to accurately determine the resultant velocity, we would need to know the magnitude and direction of the river's flow, as well as the direction of the swimmer's motion relative to the river's flow. Only then can we use vector addition to find the resultant velocity.

In conclusion, while your attempt at a solution is logical and well thought out, there are some missing pieces of information that make it difficult to accurately determine the resultant velocity. As a scientist, it is important to be precise and thorough in our problem-solving process.