NTA Abhyas JEE Main2020PhysicsWork, Power and EnergyPractice
A block of mass m is kept on a rough horizontal surface and is attached with a massless spring of force constant k . The minimum constant force applied on the other end of the spring to lift the block is
Options
- AM g
- BMg 2
- C2 M g
- DM g ( 1   +   k )
Correct answer
B. Mg 2
Step-by-step solution
As W ext = Δ E = 1 2 Kx 2  ;  F.x = 1 2 Kx 2 or F = K x 2 For lifting K x   =   M g or F = Mg 2