a$)$ Write a program to compute the area of a circle of radius r$.$

$=2$

b$)$ Write a program to compute the volume of a sphere.

$=4$

$3$

c$)$ Write a program to compute the tension in a cord given the following values:

m$1=100,$ m$2=50,$ g $=9\mathrm{.}81$

$=212$

$1+2$

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