Question

what is the buoyant force on a helium balloon with a radius
of 30 cm in air, if the density of air is 1.9 kg m3​

Answer 1

Given-

radius of helium balloon = 30 cm

density of air = 1.9 kg/m3

To find-

buoyant force

Solution-

Buoyant force = p*v*g

where p = density , v=volume , g=gravity

= {p(air)-p(he)}*v*g

={ 1.29-0.178}* 4/3πr^3*9.8

= 1.23N

Bouyant Force = 1.23N

Answer 2

$\LARGE{\mathfrak{\underline{\underline{\blue{AnSwEr:-}}}}}$

1.23 N

$\LARGE{\mathfrak{\underline{\underline{\red{Explanation}}}}}$

$\large{\mathtt{\green{Given:-}}}$

Radius of Helium Balloon = 30cm

Density of air = 1.9 kgm³

___________________________

$\large{\mathtt{\green{To \: find:-}}}$

Buoyant force

___________________________

$\large{\mathtt{\green{Solution:-}}}$

We have formula :-

$\Large{\underline{\boxed{\orange{Buoyant \: Force \: = \: p {\times} V {\times} g}}}}$

Where,

g = gravity

p = momentum

V = volume

______________[Put Values]

➭ (p of air - p of helium) × 4πr³/3 × 9.8

⇒ 1.29 - 0.178 × 4π(30)³/3 × 9.8

After Solving we get

⇒ 1.23 N

$\large{\mathbf{\star{\boxed{\purple{Force \: = \: 1.23N}}}}}$