00:06A force F is equal to 5I plus 6J plus 4K acting on a body produces a displacement S is
00:18equal
00:18to 6I minus 5K work done by the forces A 10 units B 18 units C 11 units D 5
00:30units as we have to find work so in this
00:34condition work is calculated by using formula W is equal to F dot S so work will be calculated is
00:48the value of F is given is 5I plus 6J plus 4K dot the value of displacement is given is
01:066I minus 5K
01:13so work will be obtained is is for simplification we will multiply the value of I with I the value
01:22of J with J and value of K with K here J is absent so we will neglect this because
01:31the dot product
01:33of different unit vectors will be 0 so 5 6 the 30 I dot I plus into minus it will
01:48be minus 4 5 the 20 K dot K
01:58so work done will be obtained is as we know that I dot I is equal to J dot J
02:05is equal to K dot K is equal
02:07to 1 so work done will be obtained is 30 into 1 minus 20 into 1 so work done will
02:20be obtained is 30 minus 20 so 30 minus 20 it will be
02:2610 J so the correct option will be a 10 J so the correct option will be a 10 units
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