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Learning Introductory Physics with Activities

Section 7.2 Constant Acceleration - 2D

Exercises Activities

1. A*R*C*S Throwing a Ball.

While lying on the ground, you throw a ball that flies through the air and lands on the ground a known distance \(d\) away from you after a total time \(T\text{.}\) Find the initial velocity with which you threw the ball.
Tip.
Part 1a from the A*R*C*S Steps can be especially helpful in keeping track of all the known and unknown quantities.
Answer.
Starting with the \(x\)-direction position equation:
\begin{equation*} v_{ix} = \frac{d}{T} \end{equation*}
Then using the \(y\)-direction position equation:
\begin{equation*} v_{iy} = \frac{1}{2}gT^2 \end{equation*}
And putting it all together:
\begin{equation*} \vec{v}_{i} = \frac{d}{T}\hat{x} + \frac{1}{2}gT^2\hat{y} \end{equation*}