2. A ball is thrown upwards. If the ball was thrown with an initial velocity of 20.0m/s[up] , how long does it take to reach the maximum height?

Here's how to solve this problem:<br /><br />**1. Understand the concept:**<br /><br />At the maximum height, the ball's velocity is momentarily zero before it starts falling back down. We can use this fact to solve for the time.<br /><br />**2. Identify the knowns:**<br /><br />* Initial velocity (v₀) = +20.0 m/s (positive because it's upwards)<br />* Final velocity (v) = 0 m/s (at the maximum height)<br />* Acceleration (a) = -9.8 m/s² (due to gravity, downwards, hence negative)<br /><br />**3. Choose the right equation:**<br /><br />We can use the following kinematic equation:<br /><br />v = v₀ + at<br /><br />**4. Solve for time (t):**<br /><br />* Rearrange the equation to solve for t: t = (v - v₀) / a<br />* Substitute the known values: t = (0 m/s - 20.0 m/s) / (-9.8 m/s²)<br />* Calculate: t ≈ 2.04 s<br /><br />**Answer:** It takes approximately 2.04 seconds for the ball to reach its maximum height.<br />