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Question
An object is moving along a straight line path from P to Q under the action of a force F=(4^i−3^j+2^k)N. If the co-ordinate of P & Q in metres are (3, 2, -1) & (2, -1, 4) respectively. Then the work done by the force is :
An object is moving along a straight line path from P to Q under the action of a force F=(4^i−3^j+2^k)N. If the co-ordinate of P & Q in metres are (3, 2, -1) & (2, -1, 4) respectively. Then the work done by the force is :
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Solution
The correct option is B +15J
Work done by a force is given by W=→F.→r
Here →r=−−→PQ=(2−3)^i+(−1−2)^j+(4−(−1))^k=−^i−3^j+5^k
⇒W=(4^i−3^j+2^k).(−^i−3^j+5^k)=−4+9+10=15J
Option B.
Work done by a force is given by W=→F.→r
Here →r=−−→PQ=(2−3)^i+(−1−2)^j+(4−(−1))^k=−^i−3^j+5^k
⇒W=(4^i−3^j+2^k).(−^i−3^j+5^k)=−4+9+10=15J
Option B.
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