Constant as eliptical rail `PQ` in the varticle plain with `OP = = 3m ` and `OQ= 4 m` . A block of mass `1` kg is pailed along the rail from `P` to `Q` with a force of `18 N` , which is always parallel to less `PQ` Assuming are frictionless losess , the kinetic energy the block when `0` reches `Q` is `( nxx 10)` pales . THe velie of a (Take acceleration due to gravity ) `= 10ms^(-2))`

Explanation

work done = increase in potential energy
+gain in kinetic energy
`F xx d = mgh + gain in K. E. `
`18 xx 5 = 1 xx 10 xx 4 + gin in K. E. `
`:. Gain in K.E. = 50 J =10 n`
`:. N = 5 ` .