Figure shows a light, inextensible string attached to a cart, which can slide along a frictionless horizontal rail aligned along the x axis. The left end of the string is pulled over a pulley of negligible mass and friction and fixed at height `h=3m` from the ground level. The cart slides from `x_1=3sqrt3m` to `x_2=4m` and during the move, tension in the string is kept constant at `50N`. Find the change in kinetic energy of the cart in joules. (Use `sqrt3=1.3`)

Explanation

Displacement of the point A of the string
`sqrt((3sqrt3)^2+(3)^2)-sqrt(4^2+3^2)=6-5=1m`
`DeltaK=` Work done by tension `=50xx1=50J`