Aball moving at 3.0 m/s accelerates in a straight line to 21 m/s in a time of 9.0 seconds. the acceleration of the ball was

2m/s2

Explanation:simple kinematics

vo=3m/s   , vf=21m/s ,,,t= 9s

we know that      vf=vo+at   so   a = (vf-vo)/t  =  (21-3)/9 =2m/s2

step-by-step explanation:

we are given

we have to simplify it

firstly, we will factor it

now, we can cancel like terms

now, we can combine it

so, we get

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.)