# Another Two Dimensional motion question

so use x = Xo + Voxt + .5at
to find t
by setting Vox 3.60ms

No no no. JoshMP is incorrect. You can find t using your horizontal velocity and displacement.

There is no horizontal acceleration. So Xf= Xi + Vot

Once you have t, plug it into Yf= Yi +.5(-g)t^2 and solve for Yf.

ok, than in the x = Xo + Voxt + .5at^2
i know that a = -9.8
and t = .5 cuz i did V = t/D
is Xo = o and Vox = 0?

"so would the final velocity be 3.60 m/s"

That was the question I was answering earlier when I said to use trig. You need to know the y-component to calculate the final velocity. I was not talking about finding t.

v = d/t, you've got it the wrong way around.

And no, x = 0. But initial velocity is zero.

joshMp how would you use trig if you only have one number and no degree?

You have the x component, which was given to you. Find the y component using a kinematic equation. You now have the x component and the y component of the final velocity vector. Vf^2= Vx^2 + Vy^2

"so would the final velocity be 3.60 m/s"

That was the question I was answering earlier when I said to use trig. You need to know the y-component to calculate the final velocity. I was not talking about finding t.
^ You need the final velocity to use that equation. Find the time to reach horizontal displacement, then use that time to find the vertical displacement.
My apologies, I thought the initial post (the one I've quoted second) was in response to v=d/t.

i'm confused, so in Vf^2 = Vx^2 + Vy^2
and you said that final is 3.60 m/s than what is Vx?

No. Vx= 3.6 m/s. You need to find Vy before you can find Vfinal.

oh, than to find Vy = Voy - at?

Yep.

than what is the time and Voy
i know that a = -9.8

drizzle
Gold Member
than what is the time and Voy
i know that a = -9.8

Vo is the initial velocity, you have the initial speed [17.0 m/s] and the angle [35.0° above the horizontal] and a hint:

the sine helps you solve for the vertical component.