You throw a ball straight up with an initial speed of \(10 \mathrm{~m} / \mathrm{s}\).

(a) What is the ball's instantaneous acceleration at instant \(t_{1}\), just after it leaves your hand; at instant \(t_{2}\), the top of its trajectory; and at instant \(t_{3}\), just before it hits the ground? \((b)\) What is its average acceleration for the upward portion of its journey \(\left(t_{1}\right.\) to \(\left.t_{2}\right)\) and for the entire trip \(\left(t_{1}\right.\) to \(\left.t_{3}\right)\) ?