Question

A stone of mass $1kg$ falls through the air. The air resistance acting on the stone is $2N$. Find out the acceleration of the stone? Take g= $10m/s^2$

• A. $12m/s^2$
• B. $9.8m/s^2$
• C. $8m/s^2$
• D. `$5m/s^2$
• E. $2m/s^2$

Answer 1

The correct option is C $8m/s^2$

Gravitational force acting on the stone $F=mg=1\times 10=10$ N (downward)

Air resistance force $R=2$ N (upward)

$\therefore$ Acceleration of the force $a=\frac{F-R}{m}=\frac{10-2}{1}=8$ $m/s^2$ (downward)