Physics Kinematics of a swimmer

AI Thread Summary
To determine the velocity of the current affecting a swimmer crossing a 200 m wide river, the swimmer is swept downstream 480 m in 6 minutes and 40 seconds. The correct calculation involves breaking the motion into components, focusing on the downstream displacement. The current's velocity is found by dividing the downstream distance (480 m) by the total time (400 seconds), resulting in a current speed of 1.2 m/s. The swimmer's direct crossing distance of 200 m is not relevant to this specific calculation of current velocity. Understanding the problem in terms of components is crucial for accurate results.
Hafsaaa
Messages
7
Reaction score
0
Hello I need help on the following problem:
A swimmer heading directly across a river 200 m wide reaches the opposite bank in 6 min and 40 sec she is swept downstream 480 meters, what is the velocity of the current?


Homework Statement


v = ? ; t = 6 min 40 seconds
Dx = 200
Dy= 480


Homework Equations


nzfu9y.png


The Attempt at a Solution



well I basicaly used the formula for velocity ( which is V= delta d/ delta t)
so I plugged in the numbers and converted time into 400 seconds and divided by 680 and ended up with .588
the answer is given, but its the work that matters
MY solution: .588 m/s
auctual solution: 1.2 m/s

can someone tell me where I went wrong?
 
Physics news on Phys.org
Break the motion into an x and y components. We'll say the swimmer undergoes a displacement of 480 meters in the +x direction. The time it takes for this to happen is 6 minutes and 40 seconds (400 seconds). So 480/400 = 1.2 m/s. Remember, the key to solving this is thinking about the problem in components, one where the swimmer swims at his/her speed (which doesn't even apply in this problem) and one component in which water is propelling the swimmer.
 
so the 200m is ignored?
 
Hafsaaa said:
so the 200m is ignored?
Yes.

p.s. Welcome to Physics Forums!
 
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Struggling to make relation between elastic force and height'
Hello guys this is what I tried so far. I used the UTS to calculate the force it needs when the rope tears. My idea was to make a relationship/ function that would give me the force depending on height. Yeah i couldnt find a way to solve it. I also thought about how I could use hooks law (how it was given to me in my script) with the thought of instead of having two part of a rope id have one singular rope from the middle to the top where I could find the difference in height. But the...
Back
Top