Question

I have already solved this question, but suspect the answerkey to be incorrect. Could someone please verify that by solving this exercise? Thanks.

http://i.imgur.com/81nqCqU.png
A pin P is moving simultaniously in a fixed slot of the form y=sinx and a moving slot AB. AB moves horizontally with a constant speed of 3m/s.
Find v_p and a_p .

Answer 1

First I find the time t_1 at which AB is in the shown position. As V_x is constant this is simply t_1=V_x*L=(1/3m)/(3m/s) = 1/9 s

Then I say that
x(t) = V_x*t
y(t) = sin(x(t)) = sin(V_x*t)

So
V_p={V_x,cos(V_x*t)*V_x} and a_p = {0,-sin(V_x*t)*V_x^2}

When you fill this in with the calculated t_1 you get
V_p={3,3}m/s and a_p = {0,-0.05}m/s

The answer given to me is
V_p={3,2.835}m/s and a_p = {0,-2.945}m/s
As you can see the y components are different.

Answer 2

I have found the problem. sin(x) is actually 1m*sin(1rad/m*x). My calculator was in degree mode, so I should have replaced the 1rad with 57.3°.