Question

Q .
Tension in string BC is (if string and pulley are massless)
(1) Mg /3

(2) mg

(3) 3mg /2

(4) 2mg /3 ​

Answer 1

3) 2 mg / 3

is the right .. not sure

Answer 2

Answer :

• Option (4) 2mg/3

S O L U T I O N :

For Block A,

⇒ T¹- mg = ma ---------(1)

For Block B,

⇒ T² + mg - T¹ = ma --------(2)

For Block C,

⇒ mg - T² = ma ---------(3)

Now, adding eqn. (1) , (2) & (3),

⇒ T¹ - mg + T² + mg - T¹ + mg = ma + ma + ma

⇒ mg = 3ma

⇒ g = 3a

⇒ a = g/3

Now, adding eqn. (1) & (2),

⇒ T¹ - mg + T² + mg - T¹ = ma + ma

⇒ T² = 2ma

⇒ T² = 2 × mg/3

⇒ T² = 2mg/3

Hence,

Tension in sting BC.