Under a force `(10hat(i)-3hat(j)+6hat(k))` Newton a body of mass 5 kg moves from position `(6hat(i)+5hat(j)-3hat(k))` m to position `(10hat(i)-2hat(j)
Under a force `(10hat(i)-3hat(j)+6hat(k))` Newton a body of mass 5 kg moves from position `(6hat(i)+5hat(j)-3hat(k))` m to position `(10hat(i)-2hat(j)+7hat(k))` m. Deduce the work done.
A. `-121 J`
B. 121 J
C. 242 J
D. 0 J
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Correct Answer - B
As displacement `vec(s)=vec(r_(2))-vec(r_(1))`
`i.e., vec(s)=(10hat(i)-2hat(j)+7hat(k))-(6hat(i)+5hat(j)-3hat(k))`
`=(4hat(i)-7hat(j)+10hat(k))`
So `vec(W)=vec(F).vec(s)=(10hat(i)-3hat(j)+6hat(k))(4hat(i)-7hat(j)+10hat(k))`
`i.e.,vec(W)=(40+21+60)=121" joule"`
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