Calculating Relative Velocity for Approaching Boats

AI Thread Summary
A boat is moving north at 5 m/s while another boat approaches from the southwest at 6 m/s. To find boat B's actual velocity, the relative velocity formula Vrel = Vb - Va is applied. A suggestion is made to redraw the velocity triangle to better visualize the angles, specifically using 135 degrees from the horizontal. This approach may clarify the calculation of the actual velocity of boat B. Understanding the vector components is crucial for solving the problem accurately.
ozbii
Messages
4
Reaction score
0

Homework Statement


A boat is traveling due north at 5 m/s and a passenger on boat A sees another boat, boat b, approaching from south-west (45 degrees) at a speed of 6 m/s. What is boat B's actual velocity?

Homework Equations



Vrel = Vb - Va

The Attempt at a Solution


http://blob:https%3A//www.physicsforums.com/1c3c6810-6d14-4b51-8001-acb8be8f9167 http://blob:https%3A//www.physicsforums.com/0f6caecc-b8ad-4208-b8cb-c8fdd9c98d28
upload_2015-5-13_21-19-6.png
 

Attachments

  • upload_2015-5-13_21-20-2.png
    upload_2015-5-13_21-20-2.png
    46.1 KB · Views: 512
Physics news on Phys.org
Is there a question in there somewhere? (I can't see the first two images you posted)
 
ozbii said:

Homework Statement


A boat is traveling due north at 5 m/s and a passenger on boat A sees another boat, boat b, approaching from south-west (45 degrees) at a speed of 6 m/s. What is boat B's actual velocity?

Homework Equations



Vrel = Vb - Va

The Attempt at a Solution


http://blob:https%3A//www.physicsforums.com/1c3c6810-6d14-4b51-8001-acb8be8f9167 http://blob:https%3A//www.physicsforums.com/0f6caecc-b8ad-4208-b8cb-c8fdd9c98d28 View attachment 83441
Try redrawing your triangle a little differently so that the angle is 135 degrees from the horizontal. Imagine flipping your triangle upside down.
 
Hope this helps
 

Attachments

  • Triangle.jpg
    Triangle.jpg
    9.9 KB · Views: 450

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

What is the speed of the boat relative to the water?
Replies
6
Views
4K
2D Relative Velocity regarding boats
Replies
6
Views
3K
River-boat problem (Relative velocity)
Replies
9
Views
7K
Relative velocity boat crossing a river
Replies
3
Views
3K
Velocity of boat connected by a pulley fixed at some height
Replies
6
Views
2K
Relative velocity of river flowing
Replies
4
Views
3K
Solving Joe's Tricky Boat Problem: Find Boat Speed Relative to Joe
Replies
4
Views
2K
Relative Velocity: How Far Will the Boat Move Downstream Without Correction?
Replies
1
Views
1K
Relative Velocity Problem - Finding an angle of a boat going down a river
Replies
4
Views
4K
Calculate the relative angular velocity
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top