NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Robots with telescoping arms are sometimes used to perform tasks (e.g., welding or placing screws) where access may be difficult for other robotic types. During a test run, a robot arm is programmed to extend according to the relationship $r=3+$ $0.5 \cos (4 \theta)$ and the arm rotates according to the relationship $\theta=-\frac{\pi}{4} t^{2}+\pi t$, where $r$ is in feet, $\theta$ is in radians, and $t$ is in seconds. Problem 11.161.a Polar coordinates-robot arm with radius and angle as functions of time-find velocity and acceleration Determine the velocity and acceleration of the robot tip $A$ at $t=3 \mathrm{~s}$. The velocity is $v=-$ $e_{\theta} \mathrm{ft} / \mathrm{s}$. The acceleration is $a=(-$ $e_{\theta}+$ $\left.e_{p}\right) \mathrm{ft} / \mathrm{s}^{2}$

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