<p>A tennis ball is dropped on to the floor from a height of 9.8 m. It rebounds to a height 5.0 m. Ball comes in contact with the floor for 0.2s. The average acceleration during contact is __________&nbsp;<span class="equation">\(ms^{-2}\)</span>.&nbsp;</p>

<p>(Given g = 10&nbsp;<span class="equation">\(ms^{-2}\)</span>)​​​​​​​</p>