Question

Two masses of $10kg$ and $20kg$ respectively are tied together by a massless spring. A force of $200N$ is applied on $20kg$mass as shown in figure. At the instant shown, the acceleration of $10kg$ mass is instant shown, the acceleration of $10kg$ mass is $12m/s^2$, the the acceleration of 20 kg mass.

• A. $120N$
• B. $60N$
• C. $180N$
• D. $80N$

Answer 1

The correct option is A $120N$

For $10kg$ $T=ma$

$=10\times 12$

$=120N⟶\left(1\right)$

For $20kg$ $F-T=ma$

$40-120=20a$

$a=\frac{80}{20}$

$=4m/s^2$

$\therefore$ Acceleration of $20kg=4m/s^2.$

Hence, the answer is $120N.$