Achild rolls a ball on a level floor 3.5 m to another child. if the ball makes 12.0 revolutions, what is its diameter?

d = linear distance traveled by the ball from one child to another child = 3.5 m

n = number of revolutions of the ball = 12

r = radius of the ball

C = circumference of the ball = ?

circumference of the ball is given as

C = 2πr

we know that :

linear distance traveled = number of revolutions x circumference of ball

d = n x  2πr

d =  2πr n

inserting the values

3.5 = 2 (3.14) (12) r

r = 0.046 m

D = diameter of the ball

diameter is given as

D = 2r

D = 2 (0.046)

D = 0.092 m

the current is 0.6

voltage ÷ resistance = current

so 12 ÷ 20 = 0.6

it is called kinetic energy