Boy Swim River: Time & Angle Calc

  • Thread starter Thread starter Sauk
  • Start date Start date
  • Tags Tags
    Physics
Click For Summary
SUMMARY

A boy swimming across a river with a width of 65 meters at a speed of 2.3 m/s faces a current of 1.1 m/s. To determine the time taken to cross the river, the formula time = distance/speed is applied, resulting in a crossing time of approximately 28.26 seconds. The resultant vector, combining the boy's swimming speed and the current, has a magnitude of 2.5 m/s. The angle between the resultant vector and the river bank is calculated using trigonometric functions, yielding an angle of approximately 25.57 degrees.

PREREQUISITES
  • Understanding of vector addition and resultant vectors
  • Basic knowledge of trigonometry, specifically sine and cosine functions
  • Familiarity with the concept of relative velocity in fluid dynamics
  • Ability to perform calculations involving speed, distance, and time
NEXT STEPS
  • Study vector addition in physics to understand resultant vectors
  • Learn about trigonometric functions and their applications in real-world problems
  • Explore fluid dynamics principles, particularly relative velocity
  • Practice similar problems involving swimming across currents and calculating angles
USEFUL FOR

Students in physics or mathematics, educators teaching vector analysis, and anyone interested in solving real-world problems involving motion in currents.

Sauk
Messages
6
Reaction score
0
A boy is swimming a river with a width of 65m. He is swimming from one side to the other at a constant speed of 2.3 m/s, and the current, parallel to the bank is moving at 1.1 m/s. How long will it take him to cross the river, and what will the angles be between his final path and the river bank be?
 
Physics news on Phys.org
You really should show a little more work, but just to prompt you:

You have two perpendicular vectors. One has magnitude 1.1, the other has magnitude 2.3

The resultant vector will be the actual path he follows and the resultant vector magnitude will be the actual speed he travels along that actual path

So how do you
A)Draw this? You can draw two perpendicular vectors of course, what does the resultant look like relative to those two?
B)Find the magnitude of the resultant vector?
C)Find the angle between the resultant vector and, in this case, the vector running parallel to the river bank?
 

Similar threads

  • · Replies 30 ·
2
Replies
30
Views
5K
  • · Replies 3 ·
Replies
3
Views
6K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 15 ·
Replies
15
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 16 ·
Replies
16
Views
4K
Replies
10
Views
4K
  • · Replies 22 ·
Replies
22
Views
6K