Eva twirls a stone attached to a string 2.0 meters long in a horizontal circle. At what speed must the stone move for its centripetal acceleration to be equal to the acceleration due to gravity (9.8 m/s^2)? Round your answer to the nearest tenth. m/s

4.43m/s

Explanation:

The centripetal acceleration is expressed as;

a = v²/r

v is the speed

r is the radius = 2.0m

centripetal acceleration = 9.8m/s²

Get the speed v;

v² = ar

v² = 2.0 * 9.8

v²= 19.6

v = √19.6

v = 4.43m/s

Hence the speed of the stone must be 4.43m/s

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)