Question

The masses of 10 kg and 20 kg respectively are connected by a massless spring as shown in figure. A force of 200 N acts on the 20 kg mass. At the instant shown, the 10 kg mass has acceleration $12m/se{c}^2.$ What is the acceleration of 20 kg mass

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

As the mass of 10 kg has acceleration $12m/se{c}^2$ therefore it apply 120N force on mass 20kg in a backward direction.
$\therefore$ Net forward force on 20 kg mass = 200 – 120 = 80N
$\therefore Acceleration=\frac{80}{20}=4m/s^2$