A 1.00-kg mass is attatched to a string 1.0m long and completes a horizontal circle in 0.25s. What is the centripetal acceleration and force or the mass?

-- The string is 1 m long.  That's the radius of the circle that the mass is traveling in.  The circumference of the circle is  (π) x (2R) = 2π meters .-- The speed of the mass is (2π meters) / (0.25 sec) = 8π m/s .-- Centripetal acceleration is  V²/R = (8π m/s)² / (1 m) = 64π^2 m/s²-- Force = (mass) x (acceleration) = (1kg) x (64π^2 m/s²) =                                                          64π^2 kg-m/s² = 64π^2 N = about 631.7 N .That's it.  It takes roughly a 142-pound pull on the string to keep 1 kilogram revolving at a 1-meter radius 4 times a second !  If you eased up on the string, the kilogram could keep revolving in the same circle, but not as fast.You also need to be very careful with this experiment, and use a string that can hold up to a couple hundred pounds of tension without snapping.  If you've got that thing spinning at 4 times per second and the string breaks, you've suddenly got a wild kilogram flying away from the circle in a straight line, at 8π meters per second ... about 56 miles per hour !  This could definitely be hazardous to the health of anybody who's been watching you and wondering what you're doing.