Answer
a). The string cannot be exactly horizontal because of the weight of the ball acting downwards.
b). $7.845m/s$
c). $10.25N$
Work Step by Step
a). The string cannot be exactly horizontal because of the weight of the ball acting downwards.
b). m=0.25kg,
r=1.5m, t=1.2s for 1 revolution.
$\omega=\frac{2pi}{1.2}=5.23rad/s$
$v=r\omega=1.5\times5.23=7.845m/s$
c). $F=ma_{c}=m\frac{v^{2}}{r}=10.25N$
