Consider an elliptically shaped rail PQ in the vertical plane with OP = 3 m and OQ = 4 m. A block of mass 1 kg is pulled along the rail from P to Q with a force of 18 N, which is always parallel to line PQ (see the figure given). Assuming no frictional losses, the kinetic energy of the block when it reaches Q is: `(n xx 10)` joules. The value of n is (take acceleration due to gravity = `10 ms^(-2)` )
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Answer

5

Explanation

Using work energy theorem,
`W_(mg) + W_(f) = Delta KE , -mgh + Fd = Delta KE`
`-1 xx 10 xx 4 + 18(5) = Delta KE , Delta KE = 50`.