Relative Velocity and Vector Resolution

AI Thread Summary
The discussion centers on calculating the velocity of a boat relative to the shore while rowing in a river with a current. The velocity of the boat relative to the shore is determined to be 5 m/s, forming a 3-4-5 triangle. For the components of velocity, the parallel component to the shore is 3 m/s (the river's current), while the perpendicular component is 4 m/s (the boat's speed). Participants confirm that using the triangle helps clarify these components. The calculations illustrate the relationship between the boat's movement and the river's flow.
Jacobpm64
Messages
235
Reaction score
0
You row a boat perpendicular to the shore of a river that flows at 3.0 m/s. The velocity of your boat is 4.0 m/s relative to the water.
a. What is your velocity of your boat relative to the shore?
b. What is the component of your velocity parallel to the shore? Perpendicular to it?
A was very easy... If you draw it out, you can easily see that it's a 3,4,5 triangle, so the answer to A is 5 m/s.
I'm not sure how to work out B. Which number do I use to find the components? Would the parallel to the shore component be 4 m/s? Would the perpendicular be 3 m/s? I'm not sure.. Or is it totally different numbers? Help with part B please.
 
Physics news on Phys.org
You can use the same triangle that you drew for A to work out the components for B. It's easier than you think.
 
ok, which sides am i using of the triangle? it's a 3,4,5 triangle. Am i correct in saying that the velocity component parallel to the shore is the velocity of the river (+3 m/s --- since it is flowing parallel to the shore) and the velocity component perpendicular to the shore is the velocity of the boat relative to the river (+4 m/s --- since the boat is moving in a direction perpendicular to the shore)?
 
Sounds good to me.
 
thanks a lot
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

River question (looking for angles and headings)
Replies
8
Views
2K
Stuck on a vector problem: Boating across a river
Replies
11
Views
3K
Man pulling a boat along the water with a rope (from above on a steep bank)
Replies
31
Views
1K
Fisherman's boat Relative motion
Replies
29
Views
3K
Relative velocity passing a ball between two soccer players
Replies
5
Views
2K
Adding Vectors to Find Velocity
Replies
16
Views
3K
Relative velocity of river flowing
Replies
4
Views
3K
Need Help with Vector Problem? Confused About Velocity and Angle?
Replies
2
Views
2K
Frictionless problem including momentum
Replies
5
Views
3K
Writing a vector parallel and normal to a unit vector ##\hat n##
Replies
26
Views
1K

Hot Threads

Recent Insights

Back
Top