A ball is dropped on to the floor from a height of 20 m. It rebounds to a height of 10 m. If the ball is in contact with the floor for 0.1 seconds, what is the average acceleration during contact?

• A. \[\text{142 m }{{\text{s}}^{\text{-2}}}\]                
• B. \[\text{285 m }{{\text{s}}^{\text{-2}}}\]    
• C.        \[\text{338 m }{{\text{s}}^{\text{-2}}}\]    
• D.        \[\text{564 m }{{\text{s}}^{\text{-2}}}\]