A70 kg human sprinter can accelerate from rest to 10 m/s in 3.0 s. during the same time interval, a 30 kg greyhound can go from rest to 20 m/s. what is the average power output of each? average power over a time interval δt is δe/δt.

Explanation:

Average power for the human sprinter is given as

so we have

Average power for greyhound is given as

whichever one it is, it's definitely not one that you included on the list you provided.

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s