Question

Two masses 8 kg and 12 kg are connected at the two ends of a light inextensible string that goes over a frictionless pulley. Find the acceleration of the masses, and the tension in the string when the masses are released.

Answer 1

Let ‘a’ be the acceleration of the masses. 

Then for block m₁, T – m₁g = m₁a → (1)

for block m_2, m₂g – T = m₂ a → (2)

(1) + (2) (m₂ – m₁) g = (m₁ + m₂) a

⇒ a = \(\frac{12-8}{12+8}\) g = 2m/s

substituting in (1)

T – 8 × 10 = 8 × 2

⇒ T = 96 N.