Answer:
Following are the solution to the given points:
Step-by-step explanation:
In this question, some of the values are missing, that's why its solution can be defined as follows:
In point a:
Density of air
Density of helium
![\rho_(helium) =0.178 (kg)/(m^3) \\\\](https://img.qammunity.org/2021/formulas/physics/high-school/q4d1hifph36sfwebacc9d1239yqq8ykr8q.png)
The volume of the helium balloon
![V= 2L](https://img.qammunity.org/2021/formulas/physics/high-school/yebew8wdmq3mzynv3ezfvphegfjp0rw52i.png)
![\to V= 2 * 10^(-3)](https://img.qammunity.org/2021/formulas/physics/high-school/e1lz8wz2crsshoxxjffxvs27pblzsydhkf.png)
Formula:
![F_B = e_a V g\\\\](https://img.qammunity.org/2021/formulas/physics/high-school/bpc8edzxbcjkcfjjtdxkuywl8l1mdzk72h.png)
![= 1.29 * 2 * 10^(-3) * 9.81\\\\ = 0.0253098 \ N](https://img.qammunity.org/2021/formulas/physics/high-school/v11i6qwwrz74fshytccspejis9v8z94n3c.png)
where g is the acceleration due to gravity
In point b:
![m_g= 1.5 \ g](https://img.qammunity.org/2021/formulas/physics/high-school/10dnkk86rrio510xyt5hsmilb2c22vpbni.png)
Formula:
![F_(net)=F_B - (m_r + \rho_h \ v )g](https://img.qammunity.org/2021/formulas/physics/high-school/k96d4y3s23n5rb79hkvgo8kv2hq9cc5a4v.png)
![= 0.0253098 - (1.5 * 10^(-3) + 0.178 * 2 * 10^(-3) * 9.81)\\\\= 7.10244 * 10^(-3) \ N](https://img.qammunity.org/2021/formulas/physics/high-school/83r3f32ca8crhakajkz04oey933znnlz5a.png)