How Can I Quickly Solve Basic Physics Problems for My Course?

[kathryn]

I realize that these are really easy questions, but I am just starting a correspondence course and I need to finish the first half of my physics course in less than a month to graduate. Thanks for any help!

1. A straight river with parallel banks flows at 4 km/h. A boat moves directly downstream relative to the water at 11 km/h. The velocity of the boat relative to the river bank is...____________

2. If the boat moves directly upstream relative to the water of the river of #1, at 9 km/h, its velocity to the river bank is now..._________

Thanks for any help at all...

 

[whozum]

Its moving 11km/h faster than the water is, right? So how fast is that on the stream?
If your on the freeway going 50mph relative to the ground and someone passes you going 10mph faster than you are, how fast are they going relative to the ground?

2. Its the same thing except opposite direction, try to set up a "forward direction", then if your good with vectors your good to go.

 

[thepatientmental]

Hello,

I understand that you are in need of assistance with your physics questions. It is great that you are taking a correspondence course and working towards your graduation. I am happy to help you with your questions.

1. The velocity of the boat relative to the river bank is 15 km/h. This can be calculated by using the formula v = v1 + v2, where v is the total velocity, v1 is the velocity of the river and v2 is the velocity of the boat relative to the river. Therefore, v = 4 km/h + 11 km/h = 15 km/h.

2. The velocity of the boat relative to the river bank is 5 km/h. This can be calculated by using the same formula as above, where v1 is now the velocity of the boat and v2 is the velocity of the river. Therefore, v = 9 km/h - 4 km/h = 5 km/h.

I hope this helps you with your questions. If you have any further doubts, please feel free to reach out. All the best for your course and graduation! Keep up the good work.