Answer:
0.47556 m
Explanation:
[tex]F_B[/tex] = Child supplying force = 500 N
W = Weight of foam
F = Force on air
g = Acceleration due to gravity = 9.81 m/s²
By balancing the forces we get
[tex]F+W=F_B\\\Rightarrow F_B=500+W\\\Rightarrow F_B-W=500\\\Rightarrow \dfrac{4}{3}\pi R^3(\rho_{a}-\rho_{f})g=500\\\Rightarrow R=(\dfrac{500\times 3}{4\pi (\rho_{a}-\rho_{f})g})^{\dfrac{1}{3}}\\\Rightarrow R=(\dfrac{500\times 3}{4\pi (1000-95)\times 9.81})^{\dfrac{1}{3}}\\\Rightarrow R=0.23778\ m[/tex]
The diameter of the ball is [tex]2\times 0.23778=0.47556\ m[/tex]