The starting blocks used by sprinters give them a nearly horizontal acceleration. A 58.0 kg sprinter using a starting block has a nearly horizontal acceleration with a magnitude of 14.5 m/s². 
i) Determine the horizontal force the sprinter has to exert on the starting blocks to generate the acceleration.
ii) The sprinter is propelled forward by a force from: The sprinter or the blocks.

• A. i) 568 N; ii) by the sprinter
• B. i) 568 N; ii) by the blocks
• C. i) 841 N; ii) by the sprinter
• D. i) 841 N; ii) by the blocks

Answer: (D)