NTA Abhyas JEE Main2020PhysicsWork, Power and EnergyPractice
A massless string and a spring connect two blocks A and B to each other. Block B slides over a frictionless inclined plane while block A slides over horizontal surface. Coefficient of friction between block A horizontal surface is μ = 0.2. At the instant shown blocks are moving with constant speed. Mass of block A and energy stored in spring are respectively. [ g = 10 m / s 2 , m B = 2 kg ]
Options
- A5 k g , 1 J
- B10 k g , 0.05 J
- C5 k g , 0.05 J
- D10 k g , 1 J
Correct answer
C. 5 k g , 0.05 J
Step-by-step solution
2 g s i n θ = k x = μ m A g ⇒ m A = 2 g sin θ μ g = 2 sin θ μ = 2 × 1 2 0 . 2 = 5 kg kx = 2 × 1 0 × 1 2 = 1 0 x = 1 0 1 × 1 0 3 = 1 cm ⇒ Energy = 1 2 × 1 0 3 × 1 0 - 2 2 = 0 . 0 5 Joule