Can you me with this high school problems? About projectile motion

[lanvin]

Homework Statement

I just did this question, and I just want to make sure I did it right... Can u run through it and notify me of any errors?

Homework Equations

Here is the question:
http://i299.photobucket.com/albums/mm286/lanvin12/333-1.jpg

The Attempt at a Solution

this is what I did...

V(x) = V(bx) - V(ax) = [ (4.4m/s) sin 31° ] - [ (7.8m/s) sin 25° ] = 1.030262m/s

V(y) = V(by) + V(ay) = [ (4.4m/s) cos 31° ] - [ (7.8m/s) cos 25° ] = 10.840736 m/s

V² = V(x)² + V(y)² = 10.8² + 1.03² + 118.5
V = √118.5 = 10.88

A = V / t = 10.88 / 8.55 = 1.28m/s²


tan theta = 10.84 / 1.030 = 10522
theta = tan^(-1) 10.52230 = 84.57°

therefore, the bird's acceleration was 1.3 m/s² [85° S of E]

is that right? Was I supposed to use TOA? Significant digits ok?
Any mistakes...?

 

[saltine]

I don't think it is right that the average acceleration is 85^o S of E. If that is the case, wouldn't the bird be flying south now?

 

[thomate1]

I am happy to help you with your high school problem on projectile motion. It looks like you have made a good attempt at solving the question and your calculations seem mostly correct.

To answer your question, yes, you were correct in using the TOA method to solve the problem. This method is commonly used in projectile motion problems and it looks like you have applied it correctly.

In terms of significant digits, it is always important to follow the rules of significant digits when doing calculations. In this case, since the given velocities have two significant digits, your final answer should also have two significant digits. So the bird's acceleration should be rounded to 1.3 m/s², not 1.28 m/s².

Overall, it seems like you have a good understanding of projectile motion and have solved the problem correctly. Keep up the good work! If you have any further questions or concerns, please don't hesitate to ask.