posted by donald .
a man swings his child in a circle of radius .75 meters. if the mass of the child is 25 kilograms and the child makes one revolution in 1.5 seconds, what is the magnitude and direction of the force that must be exerted by the man on the child?
Ac = w^2 r
w = 2 pi radians/1.5 seconds = 4.19 radians/second
Ac = 4.19^2 * .75 = 13.2 m/s^2
Fin = m Ac = 25*13.2 = 329 Newtons
Fup = m g = 25 * 9.81 = 245 Newtons
magnitude of force = sqrt(329^2+245^2)
tangent of direction up from horizontal = 245/329