Question

Two identical ideal springs of spring constant 1000 N/m are connected by a pulley as shown in figure and this arrangement is established in the vertical plane. The pulley is ideal and string passing over pulley is massless. At equilibrium of pulley q is 60ŗ and the masses m₁ and m₂ are 2 kg and 3 kg respectively. Then the elongation in each spring when q is 60ŗ is –

• A. 1.6 $\sqrt { 3 }$ cm
• B. 1.6 cm
• C. 4.8 cm
• D. None of these

Answer 1

Answer: (A)

1.6 $\sqrt { 3 }$ cm

Answer 2

2kx cos 30° = $\frac { 4 \mathrm {~m} _ { 1 } \mathrm {~m} _ { 2 } } { \mathrm {~m} _ { 1 } + \mathrm { m } _ { 2 } }$ g

Or

2kx cos30° = 2T ............(1)

T – m₁g = m₁a ........... (2)

m₂g – T = m₂a .............(3)