How Do You Calculate the Y-Component of Velocity in a 2D Kinematics Problem?

[creechur]

Homework Statement

A particle starts from rest at (r0) = 9m j-hat and moves in the xy-plane with the velocity shown in the figure . The particle passes through a wire hoop located at (r1)=20m i-hat, then continues onward.

https://www.physicsforums.com/attachment.php?attachmentid=7841&stc=1&d=1159234661

The question I'm having trouble with is finding the y-component of velocity at t=4

Homework Equations

I think it's v = v_i + a_y delta t

The Attempt at a Solution

I got -40 (express to only one sig fig) and it was wrong, so I have no idea what to do


Someone please just point me in the direction to go, and not to an older thread

 

[Redbelly98]

The graphs are confusing. Both claim to be of v_x as a function of time, but are clearly showing different functions. Can you explain more what the two graphs are supposed to be showing?

 

[creechur]

the first graph (positive V) is V_x the second one is v_y

 

[Redbelly98]

Okay.

If that graph is the only information we have about v_y, your question is unanswerable. Normally you would just read the value of v_y at t=4 seconds on the graph. But whoever made the graph has done it sloppily, all we have is the cryptic "4y" label for the velocity at 4 seconds. Plus they mislabelled v_x for the graph that should be v_y.

Are these graphs something your professor provided in a printout? I can't believe a textbook would have something like this, since they normally have editors and proofreaders to troubleshoot errors like this.

 

[creechur]

It actually an online site that we do our homework on, I found those graphs elsewhere. I know it has something to do with the acceleration of gravity, but I submitted the answer 40 and got counted wrong (i submitted both negative and positive