Achild on a spinning playground ride is 0.36 m from the center of the ride. the centripetal force on the child is 19 n. what is the mass of the child if the child has a tangential speed of 0.54 m/s?

Any motion in a curved path represents accelerated motion, and requires a force directed toward the center of curvature of the path. This force is called the centripetal force which means "center seeking" force. The force has the magnitude

F = mv^2 / r

Where f is the centripetal force

M is the mass

V is the velocity

R is the radius

19 N = m ( 0.54 m/s)^2 / 0.36 m

Solving for m

M = 23.5 kg

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form