Question

a force f vector equal to 4i-5j+3k acts at a point r1=i-2j+3k. the torque acting about a point r2 = 3i-2j-3k
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Answer 1

Torque = F×r

r= r2-r1 = 3i-2j-3k - (i-2j+3k)

= 3i -2j-3k-i+2j-3k

r =2i

Torque = F×r

Torque = 4i-5j+3k × 2i

Torque= -10(-k)+ 6j

Torque = 10k + 6j

So torque is 10k+6j