Question

Two masses of 10 kg and 20 kg respectively are connected by a massless spring as shown in the figure. A force of 200 N acts upon the 20 kg mass. At the instant shown, the 10 kg mass has acceleration of 12 m/s². The acceleration of 20kg mass is

(A) 12 m/s²

(B) 4 m/s²

(C) 10 m/s²

(D) Zero

Answer 1

Correct option is (B) 4 m/s²

m₁​ = 10kg; m₂​ = 20kg; F_2​ = 200N; a₁​ = 12ms⁻²; a₂ ​= ?

For mass m₁​; 

F = m₁​a_1​ 

= 10 × 12 

= 120N

For mass m₂​;

200−F = 20a₂^​

200−120 = 20a₂

a₂​ = \(\frac{80}{20}\) = 4ms⁻²