Acceleration in 2 component directions

[get_physical]

Homework Statement

Find acceleration of 100kg ship using a component solution.

Homework Equations

Fnet = ma

The Attempt at a Solution

break into x and y components? so that Fnet for x = 150cos20 + 300cos30 = 100a and so a = 4.01 in x direction.

Fnet for y = 150sin20+ 300sin30 = 100a and so a = 2.01 in y direction.

And the mg = buoyant force?

Not sure if I'm doing this right..

 

[Chestermiller]

You did the x direction correctly, but not the y direction. The second term should be -300 sin 30. There is no need to do the z direction, since the problem statement is implicitly not asking for that.

Chet

 

[get_physical]

If i do -300 then I get a negative force in the y component... does that mean the boat is moving in the south direction (south east direction?)

 

[Chestermiller]

If i do -300 then I get a negative force in the y component... does that mean the boat is moving in the south direction (south east direction?)

No. It means it's accelerating in that direction.

 

[get_physical]

oh yes a negative acceleration in the y component and a positive in the x component. does that mean it is going to get straigther and straighter in the x direction?

 

[Chestermiller]

oh yes a negative acceleration in the y component and a positive in the x component. does that mean it is going to get straigther and straighter in the x direction?

What makes you think that?

 

[get_physical]

because the acceleration is decreasing in the y component. Doesn't that mean velocity is going to become 0 in the y component? And since it's + in the x component, then it will be eventually only have velocity in the x component?

 

[Chestermiller]

No. It just means that the velocity in the y direction will become zero and then negative. As time progresses, it will become even more negative.