A man of mass 100 kg climbs up a ladder of length 10m. The ladder makes angle `60^@` with the horizontal . Find the work done by the man against gravity in climbing up the ladder . `[g= 9.8m*s^(-2)]`.

Explanation

Work done to climb up the ladder by 10 m is equivalent to the work done to climb up a vertical height h [Fig.1.9 ].

Here , `sin 60^@ =h/(10)`
`or, h=(10sqrt(3))/(2)`
`therefore` Work done, W `=mg xxh `
`=100 xx9.8 xx5sqrt(3) =8487 .04 J.`