Question

A dynamometer is attached to two bodies having masses $M=6kg$ and $m=4kg$ respectively. Forces, $F=20N$ and $f=10N$ are applied to the masses as shown in diagram. Then, the reading of the dynamometer will be

• A. $10N$
• B. $20N$
• C. $6N$
• D. $14N$

Answer 1

The correct option is D $14N$

Free body diagram of M and m is

From free body diagram of M $\left(6kg\right)$
$20-T=6a......\left(1\right)$
From free body diagram of m $\left(4kg\right)$
$T-10=4a......\left(2\right)$
On solving equation $\left(1\right)$ and $\left(2\right)$ we get,
$a=1m/s^2$
$T=14N$